From d4b25d0ebcd6dda7fc4f1284ef4819b580ed8550 Mon Sep 17 00:00:00 2001
From: Ruby Martin <ruby@wolfssl.com>
Date: Wed, 25 Mar 2026 11:07:32 -0600
Subject: [PATCH] guard against heap buffer overflow

---
 wolfcrypt/src/asn.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c
index 4dfe4150a0..a5bc9b0733 100644
--- a/wolfcrypt/src/asn.c
+++ b/wolfcrypt/src/asn.c
@@ -9151,8 +9151,13 @@ int wc_CheckPrivateKeyCert(const byte* key, word32 keySz, DecodedCert* der,
         if (ret == 0) {
             if (der->sapkiOID == RSAk || der->sapkiOID == ECDSAk) {
                 /* Simply copy the data */
-                XMEMCPY(decodedPubKey, der->sapkiDer, der->sapkiLen);
-                pubKeyLen = der->sapkiLen;
+                if ((word32)der->sapkiLen > pubKeyLen) {
+                    ret = BUFFER_E;
+                }
+                else {
+                    XMEMCPY(decodedPubKey, der->sapkiDer, der->sapkiLen);
+                    pubKeyLen = der->sapkiLen;
+                }
             }
             else {
             #if defined(WC_ENABLE_ASYM_KEY_IMPORT)