---
id: CVE-2025-69420
title: Missing ASN1_TYPE validation in TS_RESP_verify_response() function
summary: |-
  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
  processin…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: adp
cwe:
  - CWE-754
vendor: OpenSSL
product: OpenSSL
affected:
  - OpenSSL >= 3.6.0 < 3.6.1
  - OpenSSL >= 3.5.0 < 3.5.5
  - OpenSSL >= 3.4.0 < 3.4.4
  - OpenSSL >= 3.3.0 < 3.3.6
  - OpenSSL >= 3.0.0 < 3.0.19
  - OpenSSL >= 1.1.1 < 1.1.1ze
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-01-28T19:33:06.662569Z'
exploitAvailable: true
published: '2026-01-27'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T01:10:28.084Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-69420'
references:
  - url: 'https://openssl-library.org/news/secadv/20260127.txt'
    label: OpenSSL Advisory
  - url: >-
      https://github.com/openssl/openssl/commit/a99349ebfc519999edc50620abe24d599b9eb085
    label: 3.6.1 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/564fd9c73787f25693bf9e75faf7bf6bb1305d4e
    label: 3.5.5 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/27c7012c91cc986a598d7540f3079dfde2416eb9
    label: 3.4.4 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/5eb0770ffcf11b785cf374ff3c19196245e54f1b
    label: 3.3.6 git commit
  - url: >-
      https://github.com/openssl/openssl/commit/4e254b48ad93cc092be3dd62d97015f33f73133a
    label: 3.0.19 git commit
tags:
  - cve.org
  - exploit-available
epss: 0.00899
epssPercentile: 0.58775
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/Kha-Beleh/PoC-CVE-2025-69420'
  checkedAt: '2026-10-15T05:53:20.621Z'
ingestedAt: '2026-10-15T05:52:46.060Z'
---

## Overview

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.

## Affected

- `OpenSSL >= 3.6.0 < 3.6.1`
- `OpenSSL >= 3.5.0 < 3.5.5`
- `OpenSSL >= 3.4.0 < 3.4.4`
- `OpenSSL >= 3.3.0 < 3.3.6`
- `OpenSSL >= 3.0.0 < 3.0.19`
- `OpenSSL >= 1.1.1 < 1.1.1ze`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.