CVE-2026-56820
Netty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks
CVSS Score
7.4
EPSS Score
0.0%
EPSS Percentile
0th
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 | CWE-295 |
| Vendor | netty |
| Product | netty |
| Published | Jul 21, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
netty / netty
>= 4.2.0.Final, < 4.2.16.Final < 4.1.136.Final
References
github.com: https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg github.com: https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b github.com: https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6 github.com: https://github.com/netty/netty/releases/tag/netty-4.1.136.Final github.com: https://github.com/netty/netty/releases/tag/netty-4.2.16.Final