CVE-2026-56820

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and prior to 4.1.135.Final, `OcspClient` does not validate that the `CertificateID` in an OCSP response matches the requested `CertificateID`, which can lead to replay attack. `OcspClient.validateResponse` accepts a legitimately signed `GOOD` status response for an unrelated certificate issued by the same CA, allowing bypass of revocation checks for another certificate. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

• CWE-295

• https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003bPatch
• https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6Patch
• https://github.com/netty/netty/releases/tag/netty-4.1.136.FinalRelease Notes
• https://github.com/netty/netty/releases/tag/netty-4.2.16.FinalRelease Notes
• https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwgExploit, Vendor Advisory

Published

Jul 21, 2026

Last Modified

Jul 30, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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