CVE-2026-93578 — Io.netty/netty-handler-ssl-ocsp: netty: missing extended key usage (eku) check in ocsp client allows certificate revocation bypass
A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client. The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in OCSP responder certi…
Published: 2026-09-18 · CVSS: 5.9 · CVSS 3.1
A flaw was found in Netty's Online Certificate Status Protocol (OCSP) Client. The client fails to verify the 'id-kp-OCSPSigning' Extended Key Usage (EKU) in OCSP responder certificates. A remote attacker, holding any valid certificate issued by the same Certificate Authority (CA), can exploit this by forging 'GOOD' OCSP responses for revoked certificates. This bypasses certificate revocation checks, allowing applications using Netty's OCSP Client to accept certificates that should have been revoked, leading to an authorization bypass.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7