diff --git a/ChangeLog.d/fix_reporting_of_key_usage_issues.txt b/ChangeLog.d/fix_reporting_of_key_usage_issues.txt
new file mode 100644
index 0000000..b81fb42
--- /dev/null
+++ b/ChangeLog.d/fix_reporting_of_key_usage_issues.txt
@@ -0,0 +1,11 @@
+Security
+   * With TLS 1.3, when a server enables optional authentication of the
+     client, if the client-provided certificate does not have appropriate values
+     in keyUsage or extKeyUsage extensions, then the return value of
+     mbedtls_ssl_get_verify_result() would incorrectly have the
+     MBEDTLS_X509_BADCERT_KEY_USAGE and MBEDTLS_X509_BADCERT_EXT_KEY_USAGE bits
+     clear. As a result, an attacker that had a certificate valid for uses other
+     than TLS client authentication could be able to use it for TLS client
+     authentication anyway. Only TLS 1.3 servers were affected, and only with
+     optional authentication (required would abort the handshake with a fatal
+     alert).
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index 8ac6579..651a17b 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -714,6 +714,18 @@
     /*
      * Secondary checks: always done, but change 'ret' only if it was 0
      */
+    /* keyUsage */
+    if ((mbedtls_x509_crt_check_key_usage(
+             ssl->session_negotiate->peer_cert,
+             MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0)) {
+        MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
+        if (ret == 0) {
+            ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
+        }
+        verify_result |= MBEDTLS_X509_BADCERT_KEY_USAGE;
+    }
+
+    /* extKeyUsage */
     if (ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT) {
         ext_oid = MBEDTLS_OID_SERVER_AUTH;
         ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_SERVER_AUTH);
@@ -722,16 +734,14 @@
         ext_len = MBEDTLS_OID_SIZE(MBEDTLS_OID_CLIENT_AUTH);
     }
 
-    if ((mbedtls_x509_crt_check_key_usage(
-             ssl->session_negotiate->peer_cert,
-             MBEDTLS_X509_KU_DIGITAL_SIGNATURE) != 0) ||
-        (mbedtls_x509_crt_check_extended_key_usage(
+    if ((mbedtls_x509_crt_check_extended_key_usage(
              ssl->session_negotiate->peer_cert,
              ext_oid, ext_len) != 0)) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (usage extensions)"));
         if (ret == 0) {
             ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
         }
+        verify_result |= MBEDTLS_X509_BADCERT_EXT_KEY_USAGE;
     }
 
     /* mbedtls_x509_crt_verify_with_profile is supposed to report a
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index f1f85a0..b0ecfd0 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -2204,7 +2204,9 @@
             ret != MBEDTLS_ERR_SSL_CRYPTO_IN_PROGRESS) {
             mbedtls_printf(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n",
                            (unsigned int) -ret);
-            if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
+#if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
+            if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
+                ret == MBEDTLS_ERR_SSL_BAD_CERTIFICATE) {
                 mbedtls_printf(
                     "    Unable to verify the server's certificate. "
                     "Either it is invalid,\n"
@@ -2215,7 +2217,13 @@
                     "not using TLS 1.3.\n"
                     "    For TLS 1.3 server, try `ca_path=/etc/ssl/certs/`"
                     "or other folder that has root certificates\n");
+
+                flags = mbedtls_ssl_get_verify_result(&ssl);
+                char vrfy_buf[512];
+                x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), "  ! ", flags);
+                mbedtls_printf("%s\n", vrfy_buf);
             }
+#endif
             mbedtls_printf("\n");
             goto exit;
         }
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index cc895a1..714f71d 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -3505,7 +3505,8 @@
                        (unsigned int) -ret);
 
 #if defined(MBEDTLS_SSL_HANDSHAKE_WITH_CERT_ENABLED)
-        if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED) {
+        if (ret == MBEDTLS_ERR_X509_CERT_VERIFY_FAILED ||
+            ret == MBEDTLS_ERR_SSL_BAD_CERTIFICATE) {
             char vrfy_buf[512];
             flags = mbedtls_ssl_get_verify_result(&ssl);
 
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 216bbd0..531eb74 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -7640,22 +7640,26 @@
 
 # Tests for keyUsage in leaf certificates, part 1:
 # server-side certificate/suite selection
+#
+# This is only about 1.2 (for 1.3, all key exchanges use signatures).
+# In 4.0 this will probably go away as all TLS 1.2 key exchanges will use
+# signatures too, following the removal of RSA #8170 and static ECDH #9201.
 
-run_test    "keyUsage srv: RSA, digitalSignature -> (EC)DHE-RSA" \
+run_test    "keyUsage srv 1.2: RSA, digitalSignature -> (EC)DHE-RSA" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server2.key \
              crt_file=$DATA_FILES_PATH/server2.ku-ds.crt" \
             "$P_CLI" \
             0 \
             -c "Ciphersuite is TLS-[EC]*DHE-RSA-WITH-"
 
-run_test    "keyUsage srv: RSA, keyEncipherment -> RSA" \
+run_test    "keyUsage srv 1.2: RSA, keyEncipherment -> RSA" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server2.key \
              crt_file=$DATA_FILES_PATH/server2.ku-ke.crt" \
             "$P_CLI" \
             0 \
             -c "Ciphersuite is TLS-RSA-WITH-"
 
-run_test    "keyUsage srv: RSA, keyAgreement -> fail" \
+run_test    "keyUsage srv 1.2: RSA, keyAgreement -> fail" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server2.key \
              crt_file=$DATA_FILES_PATH/server2.ku-ka.crt" \
             "$P_CLI" \
@@ -7663,7 +7667,7 @@
             -C "Ciphersuite is "
 
 requires_config_enabled MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED
-run_test    "keyUsage srv: ECDSA, digitalSignature -> ECDHE-ECDSA" \
+run_test    "keyUsage srv 1.2: ECC, digitalSignature -> ECDHE-ECDSA" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server5.key \
              crt_file=$DATA_FILES_PATH/server5.ku-ds.crt" \
             "$P_CLI" \
@@ -7671,14 +7675,14 @@
             -c "Ciphersuite is TLS-ECDHE-ECDSA-WITH-"
 
 
-run_test    "keyUsage srv: ECDSA, keyAgreement -> ECDH-" \
+run_test    "keyUsage srv 1.2: ECC, keyAgreement -> ECDH-" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server5.key \
              crt_file=$DATA_FILES_PATH/server5.ku-ka.crt" \
             "$P_CLI" \
             0 \
             -c "Ciphersuite is TLS-ECDH-"
 
-run_test    "keyUsage srv: ECDSA, keyEncipherment -> fail" \
+run_test    "keyUsage srv 1.2: ECC, keyEncipherment -> fail" \
             "$P_SRV force_version=tls12 key_file=$DATA_FILES_PATH/server5.key \
              crt_file=$DATA_FILES_PATH/server5.ku-ke.crt" \
             "$P_CLI" \
@@ -7687,8 +7691,12 @@
 
 # Tests for keyUsage in leaf certificates, part 2:
 # client-side checking of server cert
+#
+# TLS 1.3 uses only signature, but for 1.2 it depends on the key exchange.
+# In 4.0 this will probably change as all TLS 1.2 key exchanges will use
+# signatures too, following the removal of RSA #8170 and static ECDH #9201.
 
-run_test    "keyUsage cli: DigitalSignature+KeyEncipherment, RSA: OK" \
+run_test    "keyUsage cli 1.2: DigitalSignature+KeyEncipherment, RSA: OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds_ke.crt" \
             "$P_CLI debug_level=1 \
@@ -7698,7 +7706,7 @@
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-"
 
-run_test    "keyUsage cli: DigitalSignature+KeyEncipherment, DHE-RSA: OK" \
+run_test    "keyUsage cli 1.2: DigitalSignature+KeyEncipherment, DHE-RSA: OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds_ke.crt" \
             "$P_CLI debug_level=1 \
@@ -7708,7 +7716,7 @@
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-"
 
-run_test    "keyUsage cli: KeyEncipherment, RSA: OK" \
+run_test    "keyUsage cli 1.2: KeyEncipherment, RSA: OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
             "$P_CLI debug_level=1 \
@@ -7718,28 +7726,32 @@
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-"
 
-run_test    "keyUsage cli: KeyEncipherment, DHE-RSA: fail" \
+run_test    "keyUsage cli 1.2: KeyEncipherment, DHE-RSA: fail (hard)" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
-            "$P_CLI debug_level=1 \
+            "$P_CLI debug_level=3 \
              force_ciphersuite=TLS-DHE-RSA-WITH-AES-128-CBC-SHA" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is TLS-"
+            -C "Ciphersuite is TLS-" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
-run_test    "keyUsage cli: KeyEncipherment, DHE-RSA: fail, soft" \
+run_test    "keyUsage cli 1.2: KeyEncipherment, DHE-RSA: fail (soft)" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
-            "$P_CLI debug_level=1 auth_mode=optional \
+            "$P_CLI debug_level=3 auth_mode=optional \
              force_ciphersuite=TLS-DHE-RSA-WITH-AES-128-CBC-SHA" \
             0 \
             -c "bad certificate (usage extensions)" \
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-" \
+            -C "send alert level=2 message=43" \
             -c "! Usage does not match the keyUsage extension"
 
-run_test    "keyUsage cli: DigitalSignature, DHE-RSA: OK" \
+run_test    "keyUsage cli 1.2: DigitalSignature, DHE-RSA: OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
             "$P_CLI debug_level=1 \
@@ -7749,30 +7761,46 @@
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-"
 
-run_test    "keyUsage cli: DigitalSignature, RSA: fail" \
+run_test    "keyUsage cli 1.2: DigitalSignature, RSA: fail (hard)" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
-            "$P_CLI debug_level=1 \
+            "$P_CLI debug_level=3 \
              force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is TLS-"
+            -C "Ciphersuite is TLS-" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
-run_test    "keyUsage cli: DigitalSignature, RSA: fail, soft" \
+run_test    "keyUsage cli 1.2: DigitalSignature, RSA: fail (soft)" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
-            "$P_CLI debug_level=1 auth_mode=optional \
+            "$P_CLI debug_level=3 auth_mode=optional \
              force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
             0 \
             -c "bad certificate (usage extensions)" \
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-" \
+            -C "send alert level=2 message=43" \
             -c "! Usage does not match the keyUsage extension"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
+run_test    "keyUsage cli 1.3: DigitalSignature, RSA: OK" \
+            "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server2.key \
+             -cert $DATA_FILES_PATH/server2-sha256.ku-ds.crt" \
+            "$P_CLI debug_level=3" \
+            0 \
+            -C "bad certificate (usage extensions)" \
+            -C "Processing of the Certificate handshake message failed" \
+            -c "Ciphersuite is"
+
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
+                             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
 run_test    "keyUsage cli 1.3: DigitalSignature+KeyEncipherment, RSA: OK" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2-sha256.ku-ds_ke.crt" \
@@ -7785,26 +7813,32 @@
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "keyUsage cli 1.3: KeyEncipherment, RSA: fail" \
+run_test    "keyUsage cli 1.3: KeyEncipherment, RSA: fail (hard)" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2-sha256.ku-ke.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is"
+            -C "Ciphersuite is" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "keyUsage cli 1.3: KeyAgreement, RSA: fail" \
+run_test    "keyUsage cli 1.3: KeyAgreement, RSA: fail (hard)" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2-sha256.ku-ka.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is"
+            -C "Ciphersuite is" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
@@ -7821,32 +7855,40 @@
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "keyUsage cli 1.3: KeyEncipherment, ECDSA: fail" \
+run_test    "keyUsage cli 1.3: KeyEncipherment, ECDSA: fail (hard)" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.ku-ke.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is"
+            -C "Ciphersuite is" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "keyUsage cli 1.3: KeyAgreement, ECDSA: fail" \
+run_test    "keyUsage cli 1.3: KeyAgreement, ECDSA: fail (hard)" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.ku-ka.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is"
+            -C "Ciphersuite is" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 # Tests for keyUsage in leaf certificates, part 3:
 # server-side checking of client cert
+#
+# Here, both 1.2 and 1.3 only use signatures.
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "keyUsage cli-auth: RSA, DigitalSignature: OK" \
+run_test    "keyUsage cli-auth 1.2: RSA, DigitalSignature: OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
@@ -7856,25 +7898,40 @@
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "keyUsage cli-auth: RSA, KeyEncipherment: fail (soft)" \
+run_test    "keyUsage cli-auth 1.2: RSA, DigitalSignature+KeyEncipherment: OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server2.key \
+             -cert $DATA_FILES_PATH/server2.ku-ds_ke.crt" \
+            0 \
+            -s "Verifying peer X.509 certificate... ok" \
+            -S "bad certificate (usage extensions)" \
+            -S "Processing of the Certificate handshake message failed"
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test    "keyUsage cli-auth 1.2: RSA, KeyEncipherment: fail (soft)" \
+            "$P_SRV debug_level=3 auth_mode=optional" \
+            "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
+            -S "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "keyUsage cli-auth: RSA, KeyEncipherment: fail (hard)" \
-            "$P_SRV debug_level=1 force_version=tls12 auth_mode=required" \
+run_test    "keyUsage cli-auth 1.2: RSA, KeyEncipherment: fail (hard)" \
+            "$P_SRV debug_level=3 force_version=tls12 auth_mode=required" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
             1 \
             -s "bad certificate (usage extensions)" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
             -s "Processing of the Certificate handshake message failed"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "keyUsage cli-auth: ECDSA, DigitalSignature: OK" \
+run_test    "keyUsage cli-auth 1.2: ECDSA, DigitalSignature: OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.ku-ds.crt" \
@@ -7884,14 +7941,28 @@
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "keyUsage cli-auth: ECDSA, KeyAgreement: fail (soft)" \
-            "$P_SRV debug_level=1 auth_mode=optional" \
+run_test    "keyUsage cli-auth 1.2: ECDSA, KeyAgreement: fail (soft)" \
+            "$P_SRV debug_level=3 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.ku-ka.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
+            -S "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
             -S "Processing of the Certificate handshake message failed"
 
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test    "keyUsage cli-auth 1.2: ECDSA, KeyAgreement: fail (hard)" \
+            "$P_SRV debug_level=3 auth_mode=required" \
+            "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
+             -cert $DATA_FILES_PATH/server5.ku-ka.crt" \
+            1 \
+            -s "bad certificate (usage extensions)" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
+            -s "Processing of the Certificate handshake message failed"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
+
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
@@ -7907,17 +7978,46 @@
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "keyUsage cli-auth 1.3: RSA, KeyEncipherment: fail (soft)" \
+run_test    "keyUsage cli-auth 1.3: RSA, DigitalSignature+KeyEncipherment: OK" \
             "$P_SRV debug_level=1 force_version=tls13 auth_mode=optional" \
             "$O_NEXT_CLI_NO_CERT -key $DATA_FILES_PATH/server2.key \
+             -cert $DATA_FILES_PATH/server2-sha256.ku-ds_ke.crt" \
+            0 \
+            -s "Verifying peer X.509 certificate... ok" \
+            -S "bad certificate (usage extensions)" \
+            -S "Processing of the Certificate handshake message failed"
+
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
+                             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
+run_test    "keyUsage cli-auth 1.3: RSA, KeyEncipherment: fail (soft)" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=optional" \
+            "$O_NEXT_CLI_NO_CERT -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2-sha256.ku-ke.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
+            -S "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
             -S "Processing of the Certificate handshake message failed"
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
+run_test    "keyUsage cli-auth 1.3: RSA, KeyEncipherment: fail (hard)" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=required" \
+            "$P_CLI key_file=$DATA_FILES_PATH/server2.key \
+             crt_file=$DATA_FILES_PATH/server2-sha256.ku-ke.crt" \
+            1 \
+            -s "bad certificate (usage extensions)" \
+            -s "Processing of the Certificate handshake message failed" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
+            -s "! mbedtls_ssl_handshake returned"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
+
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
+                             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
 run_test    "keyUsage cli-auth 1.3: ECDSA, DigitalSignature: OK" \
             "$P_SRV debug_level=1 force_version=tls13 auth_mode=optional" \
             "$O_NEXT_CLI_NO_CERT -key $DATA_FILES_PATH/server5.key \
@@ -7931,13 +8031,29 @@
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
 run_test    "keyUsage cli-auth 1.3: ECDSA, KeyAgreement: fail (soft)" \
-            "$P_SRV debug_level=1 force_version=tls13 auth_mode=optional" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=optional" \
             "$O_NEXT_CLI_NO_CERT -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.ku-ka.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
+            -s "! Usage does not match the keyUsage extension" \
             -S "Processing of the Certificate handshake message failed"
 
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
+                             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
+run_test    "keyUsage cli-auth 1.3: ECDSA, KeyAgreement: fail (hard)" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=required" \
+            "$P_CLI key_file=$DATA_FILES_PATH/server5.key \
+             crt_file=$DATA_FILES_PATH/server5.ku-ka.crt" \
+            1 \
+            -s "bad certificate (usage extensions)" \
+            -s "Processing of the Certificate handshake message failed" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the keyUsage extension" \
+            -s "! mbedtls_ssl_handshake returned"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
+
 # Tests for extendedKeyUsage, part 1: server-side certificate/suite selection
 
 requires_key_exchange_with_cert_in_tls12_or_tls13_enabled
@@ -7971,7 +8087,7 @@
 # Tests for extendedKeyUsage, part 2: client-side checking of server cert
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli: serverAuth -> OK" \
+run_test    "extKeyUsage cli 1.2: serverAuth -> OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-srv.crt" \
             "$P_CLI debug_level=1" \
@@ -7981,7 +8097,7 @@
             -c "Ciphersuite is TLS-"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli: serverAuth,clientAuth -> OK" \
+run_test    "extKeyUsage cli 1.2: serverAuth,clientAuth -> OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-srv_cli.crt" \
             "$P_CLI debug_level=1" \
@@ -7991,7 +8107,7 @@
             -c "Ciphersuite is TLS-"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli: codeSign,anyEKU -> OK" \
+run_test    "extKeyUsage cli 1.2: codeSign,anyEKU -> OK" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs_any.crt" \
             "$P_CLI debug_level=1" \
@@ -8001,14 +8117,30 @@
             -c "Ciphersuite is TLS-"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli: codeSign -> fail" \
+run_test    "extKeyUsage cli 1.2: codeSign -> fail (soft)" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3 auth_mode=optional" \
+            0 \
+            -c "bad certificate (usage extensions)" \
+            -C "Processing of the Certificate handshake message failed" \
+            -c "Ciphersuite is TLS-" \
+            -C "send alert level=2 message=43" \
+            -c "! Usage does not match the extendedKeyUsage extension"
+            # MBEDTLS_X509_BADCERT_EXT_KEY_USAGE  -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test    "extKeyUsage cli 1.2: codeSign -> fail (hard)" \
+            "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server5.key \
+             -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is TLS-"
+            -C "Ciphersuite is TLS-" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the extendedKeyUsage extension"
+            # MBEDTLS_X509_BADCERT_EXT_KEY_USAGE  -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
@@ -8049,19 +8181,22 @@
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
-run_test    "extKeyUsage cli 1.3: codeSign -> fail" \
+run_test    "extKeyUsage cli 1.3: codeSign -> fail (hard)" \
             "$O_NEXT_SRV_NO_CERT -tls1_3 -num_tickets=0 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
-            "$P_CLI debug_level=1" \
+            "$P_CLI debug_level=3" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is"
+            -C "Ciphersuite is" \
+            -c "send alert level=2 message=43" \
+            -c "! Usage does not match the extendedKeyUsage extension"
+            # MBEDTLS_X509_BADCERT_EXT_KEY_USAGE  -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 # Tests for extendedKeyUsage, part 3: server-side checking of client cert
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli-auth: clientAuth -> OK" \
+run_test    "extKeyUsage cli-auth 1.2: clientAuth -> OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cli.crt" \
@@ -8070,7 +8205,7 @@
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli-auth: serverAuth,clientAuth -> OK" \
+run_test    "extKeyUsage cli-auth 1.2: serverAuth,clientAuth -> OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-srv_cli.crt" \
@@ -8079,7 +8214,7 @@
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli-auth: codeSign,anyEKU -> OK" \
+run_test    "extKeyUsage cli-auth 1.2: codeSign,anyEKU -> OK" \
             "$P_SRV debug_level=1 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs_any.crt" \
@@ -8088,22 +8223,27 @@
             -S "Processing of the Certificate handshake message failed"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli-auth: codeSign -> fail (soft)" \
-            "$P_SRV debug_level=1 auth_mode=optional" \
+run_test    "extKeyUsage cli-auth 1.2: codeSign -> fail (soft)" \
+            "$P_SRV debug_level=3 auth_mode=optional" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
-            -S "Processing of the Certificate handshake message failed"
+            -S "send alert level=2 message=43" \
+            -s "! Usage does not match the extendedKeyUsage extension" \
+            -S "Processing of the Certificate handshake message failed" \
 
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
-run_test    "extKeyUsage cli-auth: codeSign -> fail (hard)" \
-            "$P_SRV debug_level=1 auth_mode=required" \
+run_test    "extKeyUsage cli-auth 1.2: codeSign -> fail (hard)" \
+            "$P_SRV debug_level=3 auth_mode=required" \
             "$O_CLI -tls1_2 -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
             1 \
             -s "bad certificate (usage extensions)" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the extendedKeyUsage extension" \
             -s "Processing of the Certificate handshake message failed"
+            # MBEDTLS_X509_BADCERT_EXT_KEY_USAGE  -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 requires_openssl_tls1_3_with_compatible_ephemeral
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
@@ -8142,13 +8282,29 @@
 requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
                              MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
 run_test    "extKeyUsage cli-auth 1.3: codeSign -> fail (soft)" \
-            "$P_SRV debug_level=1 force_version=tls13 auth_mode=optional" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=optional" \
             "$O_NEXT_CLI_NO_CERT -key $DATA_FILES_PATH/server5.key \
              -cert $DATA_FILES_PATH/server5.eku-cs.crt" \
             0 \
             -s "bad certificate (usage extensions)" \
+            -S "send alert level=2 message=43" \
+            -s "! Usage does not match the extendedKeyUsage extension" \
             -S "Processing of the Certificate handshake message failed"
 
+requires_openssl_tls1_3_with_compatible_ephemeral
+requires_all_configs_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE \
+                             MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED
+run_test    "extKeyUsage cli-auth 1.3: codeSign -> fail (hard)" \
+            "$P_SRV debug_level=3 force_version=tls13 auth_mode=required" \
+            "$P_CLI key_file=$DATA_FILES_PATH/server5.key \
+             crt_file=$DATA_FILES_PATH/server5.eku-cs.crt" \
+            1 \
+            -s "bad certificate (usage extensions)" \
+            -s "send alert level=2 message=43" \
+            -s "! Usage does not match the extendedKeyUsage extension" \
+            -s "Processing of the Certificate handshake message failed"
+            # MBEDTLS_X509_BADCERT_EXT_KEY_USAGE  -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
+
 # Tests for DHM parameters loading
 
 run_test    "DHM parameters: reference" \