CVE-2025-69420: Issue summary: A type confusion vulnerability exists in the TimeStamp Response verification code where an ASN1_TYPE union member is accessed without f...

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.77%

50.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-754

Affected Software

Vendor	Product	Versions
Openssl	Openssl	>= 1.1.1, < 1.1.1ze
Openssl	Openssl	>= 3.0.0, < 3.0.19
Openssl	Openssl	>= 3.3.0, < 3.3.6
Openssl	Openssl	>= 3.4.0, < 3.4.4
Openssl	Openssl	>= 3.5.0, < 3.5.5
Openssl	Openssl	>= 3.6.0, < 3.6.1

References

Timeline

Published: Jan 27, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-69420?

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.

How severe is CVE-2025-69420?

CVE-2025-69420 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.77% probability of exploitation in the next 30 days.

How do I fix CVE-2025-69420?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.