diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 873f909..3b7fc83 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1744,10 +1744,11 @@
     /* Update checksum with either
      * - The entire content of the CH message, if no PSK extension is present
      * - The content up to but excluding the PSK extension, if present.
+     * Always parse the pre-shared key extension when present in the
+     * ClientHello even if some pre-requisites for PSK key exchange modes are
+     * not met. That way we always validate the syntax of the extension.
      */
-    /* If we've settled on a PSK-based exchange, parse PSK identity ext */
-    if (ssl_tls13_key_exchange_is_psk_available(ssl) ||
-        ssl_tls13_key_exchange_is_psk_ephemeral_available(ssl)) {
+    if (handshake->received_extensions & MBEDTLS_SSL_EXT_MASK(PRE_SHARED_KEY)) {
         ret = handshake->update_checksum(ssl, buf,
                                          pre_shared_key_ext - buf);
         if (0 != ret) {
diff --git a/tests/opt-testcases/tls13-kex-modes.sh b/tests/opt-testcases/tls13-kex-modes.sh
index 4581bc5..6556cd4 100755
--- a/tests/opt-testcases/tls13-kex-modes.sh
+++ b/tests/opt-testcases/tls13-kex-modes.sh
@@ -550,7 +550,7 @@
             -s "found pre_shared_key extension" \
             -S "Found PSK_EPHEMERAL KEX MODE" \
             -s "Found PSK KEX MODE" \
-            -S "Pre shared key found" \
+            -s "Pre shared key found" \
             -S "No matched PSK or ticket" \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
@@ -733,7 +733,7 @@
             -s "found pre_shared_key extension" \
             -s "Found PSK_EPHEMERAL KEX MODE" \
             -S "Found PSK KEX MODE" \
-            -S "Pre shared key found" \
+            -s "Pre shared key found" \
             -S "No matched PSK or ticket" \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \
@@ -1413,7 +1413,7 @@
             -s "found pre_shared_key extension" \
             -s "Found PSK_EPHEMERAL KEX MODE" \
             -S "Found PSK KEX MODE" \
-            -S "Pre shared key found" \
+            -s "Pre shared key found" \
             -S "No matched PSK or ticket" \
             -S "key exchange mode: psk$"  \
             -S "key exchange mode: psk_ephemeral"  \