Missing ASN1_TYPE validation in TS_RESP_verify_response() function_CVE-2025-69420

7.5 / 10

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

Issue summary: A type confusion vulnerability exists in the TimeStamp Response
verification code where an ASN1_TYPE union member is accessed without first
validating the type, causing an invalid or NULL pointer dereference when
processing a malformed TimeStamp Response file.

Impact summary: An application calling TS_RESP_verify_response() with a
malformed TimeStamp Response can be caused to dereference an invalid or
NULL pointer when reading, resulting in a Denial of Service.

The functions ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2()
access the signing cert attribute value without validating its type.
When the type is not V_ASN1_SEQUENCE, this results in accessing invalid memory
through the ASN1_TYPE union, causing a crash.

Exploiting this vulnerability requires an attacker to provide a malformed
TimeStamp Response to an application that verifies timestamp responses. The
TimeStamp protocol (RFC 3161) is not widely used and the impact of the
exploit is just a Denial of Service. For these reasons the issue was
assessed as Low severity.

The FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,
as the TimeStamp Response implementation is outside the OpenSSL FIPS module
boundary.

OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.

OpenSSL 1.0.2 is not affected by this issue.

Basic Information

ID CVE-2025-69420

Source openssl

Published Jan 27, 2026 at 16:01

Modified Jan 28, 2026 at 19:33

Affected Product

Vendor OpenSSL

Product OpenSSL

Version 3.6.0

Affected Versions OpenSSL OpenSSL 3.6.0
OpenSSL OpenSSL 3.5.0
OpenSSL OpenSSL 3.4.0
OpenSSL OpenSSL 3.3.0
OpenSSL OpenSSL 3.0.0
OpenSSL OpenSSL 1.1.1

CWE Classification

CWE-754

References

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    "lastseen": "",
    "description": "Issue summary: A type confusion vulnerability exists in the TimeStamp Response\nverification code where an ASN1_TYPE union member is accessed without first\nvalidating the type, causing an invalid or NULL pointer dereference when\nprocessing a malformed TimeStamp Response file.\n\nImpact summary: An application calling TS_RESP_verify_response() with a\nmalformed TimeStamp Response can be caused to dereference an invalid or\nNULL pointer when reading, resulting in a Denial of Service.\n\nThe functions ossl_ess_get_signing_cert() and ossl_ess_get_signing_cert_v2()\naccess the signing cert attribute value without validating its type.\nWhen the type is not V_ASN1_SEQUENCE, this results in accessing invalid memory\nthrough the ASN1_TYPE union, causing a crash.\n\nExploiting this vulnerability requires an attacker to provide a malformed\nTimeStamp Response to an application that verifies timestamp responses. The\nTimeStamp protocol (RFC 3161) is not widely used and the impact of the\nexploit is just a Denial of Service. For these reasons the issue was\nassessed as Low severity.\n\nThe FIPS modules in 3.5, 3.4, 3.3 and 3.0 are not affected by this issue,\nas the TimeStamp Response implementation is outside the OpenSSL FIPS module\nboundary.\n\nOpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue.\n\nOpenSSL 1.0.2 is not affected by this issue.",
    "published": "2026-01-27T16:01:25.643Z",
    "modified": "2026-01-28T19:33:41.253Z",
    "type": "cve",
    "title": "Missing ASN1_TYPE validation in TS_RESP_verify_response() function",
    "source": "openssl",
    "references": "https://openssl-library.org/news/secadv/20260127.txt\nhttps://github.com/openssl/openssl/commit/a99349ebfc519999edc50620abe24d599b9eb085\nhttps://github.com/openssl/openssl/commit/564fd9c73787f25693bf9e75faf7bf6bb1305d4e\nhttps://github.com/openssl/openssl/commit/27c7012c91cc986a598d7540f3079dfde2416eb9\nhttps://github.com/openssl/openssl/commit/5eb0770ffcf11b785cf374ff3c19196245e54f1b\nhttps://github.com/openssl/openssl/commit/4e254b48ad93cc092be3dd62d97015f33f73133a",
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