diff --git a/library/x509_crt.c b/library/x509_crt.c
index 59a6946..c6d7358 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -641,10 +641,13 @@
                                  MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
     }
 
-    if ((ret = mbedtls_asn1_get_tag(p, end, &len,
-                                    MBEDTLS_ASN1_CONTEXT_SPECIFIC)) != 0) {
-        /* KeyIdentifier is an OPTIONAL field */
-    } else {
+    ret = mbedtls_asn1_get_tag(p, end, &len,
+                               MBEDTLS_ASN1_CONTEXT_SPECIFIC);
+
+    /* KeyIdentifier is an OPTIONAL field */
+    if (ret != 0 && ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
+    } else if (ret == 0) {
         authority_key_id->keyIdentifier.len = len;
         authority_key_id->keyIdentifier.p = *p;
         /* Setting tag of the keyIdentfier intentionally to 0x04.
@@ -663,26 +666,24 @@
             /* authorityCertIssuer and authorityCertSerialNumber MUST both
                be present or both be absent. At this point we expect to have both. */
             return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
-        } else {
-            /* "end" also includes the CertSerialNumber field so "len" shall be used */
-            ret = mbedtls_x509_get_subject_alt_name_ext(p,
-                                                        (*p+len),
-                                                        &authority_key_id->authorityCertIssuer);
-            if (ret != 0) {
-                return ret;
-            }
-
-            /* Getting authorityCertSerialNumber using the required specific class tag [2] */
-            if ((ret = mbedtls_asn1_get_tag(p, end, &len,
-                                            MBEDTLS_ASN1_CONTEXT_SPECIFIC | 2)) != 0) {
-                return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
-            } else {
-                authority_key_id->authorityCertSerialNumber.len = len;
-                authority_key_id->authorityCertSerialNumber.p = *p;
-                authority_key_id->authorityCertSerialNumber.tag = MBEDTLS_ASN1_INTEGER;
-                *p += len;
-            }
         }
+        /* "end" also includes the CertSerialNumber field so "len" shall be used */
+        ret = mbedtls_x509_get_subject_alt_name_ext(p,
+                                                    (*p+len),
+                                                    &authority_key_id->authorityCertIssuer);
+        if (ret != 0) {
+            return ret;
+        }
+
+        /* Getting authorityCertSerialNumber using the required specific class tag [2] */
+        if ((ret = mbedtls_asn1_get_tag(p, end, &len,
+                                        MBEDTLS_ASN1_CONTEXT_SPECIFIC | 2)) != 0) {
+            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_X509_INVALID_EXTENSIONS, ret);
+        }
+        authority_key_id->authorityCertSerialNumber.len = len;
+        authority_key_id->authorityCertSerialNumber.p = *p;
+        authority_key_id->authorityCertSerialNumber.tag = MBEDTLS_ASN1_INTEGER;
+        *p += len;
     }
 
     if (*p != end) {
diff --git a/tests/suites/test_suite_x509parse.data b/tests/suites/test_suite_x509parse.data
index 70f1e6e..3075667 100644
--- a/tests/suites/test_suite_x509parse.data
+++ b/tests/suites/test_suite_x509parse.data
@@ -3190,6 +3190,10 @@
 depends_on:MBEDTLS_MD_CAN_SHA1:MBEDTLS_RSA_C
 x509_crt_parse_authoritykeyid:"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":0:"":0:MBEDTLS_ERR_X509_INVALID_EXTENSIONS+MBEDTLS_ERR_ASN1_UNEXPECTED_TAG
 
+X509 CRT parse Authority Key Id - Wrong KeyId Tag Length
+depends_on:MBEDTLS_MD_CAN_SHA256:MBEDTLS_RSA_C
+x509_crt_parse_authoritykeyid:"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":0:"":0:MBEDTLS_ERR_X509_INVALID_EXTENSIONS+MBEDTLS_ERR_ASN1_INVALID_LENGTH
+
 X509 CRT parse Authority Key Id - Wrong Issuer Tag 1
 depends_on:MBEDTLS_MD_CAN_SHA1:MBEDTLS_RSA_C
 x509_crt_parse_authoritykeyid:"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":0:"":0:MBEDTLS_ERR_X509_INVALID_EXTENSIONS+MBEDTLS_ERR_ASN1_UNEXPECTED_TAG