From 6453d278557c8719233793730ec500c84aea55d9 Mon Sep 17 00:00:00 2001
From: Bob Beck <beck@openssl.org>
Date: Wed, 7 Jan 2026 11:29:48 -0700
Subject: [PATCH] Verify ASN1 object's types before attempting to access them
 as a particular type

Issue was reported in ossl_ess_get_signing_cert but is also present in
ossl_ess_get_signing_cert_v2.

Fixes: https://github.com/openssl/srt/issues/61
Fixes CVE-2025-69420
---
 crypto/ts/ts_rsp_verify.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/crypto/ts/ts_rsp_verify.c b/crypto/ts/ts_rsp_verify.c
index 3876e30f47b..40dab687d1c 100644
--- a/crypto/ts/ts_rsp_verify.c
+++ b/crypto/ts/ts_rsp_verify.c
@@ -209,7 +209,7 @@ static ESS_SIGNING_CERT *ossl_ess_get_signing_cert(const PKCS7_SIGNER_INFO *si)
     const unsigned char *p;
 
     attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificate);
-    if (attr == NULL)
+    if (attr == NULL || attr->type != V_ASN1_SEQUENCE)
         return NULL;
     p = attr->value.sequence->data;
     return d2i_ESS_SIGNING_CERT(NULL, &p, attr->value.sequence->length);
@@ -221,7 +221,7 @@ static ESS_SIGNING_CERT_V2 *ossl_ess_get_signing_cert_v2(const PKCS7_SIGNER_INFO
     const unsigned char *p;
 
     attr = PKCS7_get_signed_attribute(si, NID_id_smime_aa_signingCertificateV2);
-    if (attr == NULL)
+    if (attr == NULL || attr->type != V_ASN1_SEQUENCE)
         return NULL;
     p = attr->value.sequence->data;
     return d2i_ESS_SIGNING_CERT_V2(NULL, &p, attr->value.sequence->length);
