CVE-2026-56821: Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator

July 22, 2026

OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response to bypass revocation of a since-revoked certificate.

References

github.com/advisories/GHSA-g7hg-vrcf-mvmr
github.com/netty/netty/releases/tag/netty-4.1.136.Final
github.com/netty/netty/releases/tag/netty-4.2.16.Final
github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr
nvd.nist.gov/vuln/detail/CVE-2026-56821

Code Behaviors & Features

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