OCSP stapling is a TLS feature that lets a server send a recent certificate-status response during the handshake. Instead of forcing every client to contact the certificate authority’s OCSP responder, the server “staples” the proof of revocation status to the connection. This lowers latency, reduces external lookups, and makes certificate validation more reliable for clients behind firewalls or privacy controls.
In cyber security, OCSP stapling matters because it sits directly in the trust path. Defenders use it to improve performance and availability, while attackers may try to abuse weaknesses in the code that parses or verifies stapled responses. If that parsing logic is flawed, a malformed OCSP response can cause handshake failures, crashes, or other availability problems in TLS libraries and applications. For this reason, administrators should know whether OCSP stapling is enabled, which services depend on it, and whether their TLS stack has current fixes for OCSP handling.