diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 99ff5382b627..c02c200a7136 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -525,7 +525,7 @@ int x509_decode_time(time64_t *_t,  size_t hdrlen,
 	}
 
 	if (day < 1 || day > mon_len ||
-	    hour > 23 ||
+	    hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */
 	    min > 59 ||
 	    sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */
 		goto invalid_time;