Type Confusion Vulnerability in OpenSSL Affecting TimeStamp Responses

CVE-2025-69420

What is CVE-2025-69420?

A type confusion vulnerability exists within OpenSSL's TimeStamp Response verification code, which can lead to Denial of Service. When an invalid type is accessed without preliminary validation, applications invoking TS_RESP_verify_response() with a malformed TimeStamp Response can experience a memory crash due to dereferencing invalid pointers. This flaw specifically affects OpenSSL versions 3.6, 3.5, 3.4, 3.3, and 3.0, as the handling of ASN1_TYPE unions allows for these problematic memory accesses, making the exploitation possible through deliberately crafted Timestamp Responses.

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