1 files changed, 7 insertions, 5 deletions

diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 3000ea3b6687..021d39c0ba75 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -531,7 +531,11 @@ int x509_decode_time(time64_t *_t,  size_t hdrlen,
         if (*p != 'Z')
                 goto unsupported_time;
 
-        mon_len = month_lengths[mon];
+        if (year < 1970 ||
+            mon < 1 || mon > 12)
+                goto invalid_time;
+
+        mon_len = month_lengths[mon - 1];
         if (mon == 2) {
                 if (year % 4 == 0) {
                         mon_len = 29;
@@ -543,14 +547,12 @@ int x509_decode_time(time64_t *_t,  size_t hdrlen,
                 }
         }
 
-        if (year < 1970 ||
-            mon < 1 || mon > 12 ||
-            day < 1 || day > mon_len ||
+        if (day < 1 || day > mon_len ||
             hour > 23 ||
             min > 59 ||
             sec > 59)
                 goto invalid_time;
-        
+
         *_t = mktime64(year, mon, day, hour, min, sec);
         return 0;