Use-After-Free in X.509 Extension Cache Under Concurrent Use

Issue summary: The first concurrent use of the same X.509 certificate by several threads may cause its cached extension data to be freed while another thread is still using it. Impact summary: A remote, unauthenticated peer could crash a multi-threaded TLS client, or a multi-threaded TLS server...

PT-2026-102659

Name of the Vulnerable Software and Affected Versions OpenSSL version 4.0 Description A use-after-free read occurs when multiple threads concurrently use the same X.509 certificate for the first time. OpenSSL caches decoded X.509v3 extension values in two phases: computation under a read lock and...