CVE-2026-56820
HIGHNetty: Missing CertificateID Validation in OCSP Response Allows Replay Attacks
Title source: cnaDescription
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.
References (5)
Core 5
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/netty/netty/security/advisories/GHSA-272m-gcwp-mpwg
X_Refsource_Misc x_refsource_misc
https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
X_Refsource_Misc x_refsource_misc
https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
X_Refsource_Misc x_refsource_misc
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
X_Refsource_Misc x_refsource_misc
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
Scores
CVSS v3
7.4
EPSS
0.0018
EPSS Percentile
8.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
poc
Automatable
no
Technical Impact
total
Details
CWE
CWE-295
Status
published
Products (5)
io.netty/netty-handler-ssl-ocsp
0 - 4.1.136.FinalMaven
io.netty/netty-handler-ssl-ocsp
4.2.0.Final - 4.2.16.FinalMaven
netty/netty
< 4.1.136
netty/netty
< 4.1.136.Final
netty/netty
>= 4.2.0.Final, < 4.2.16.Final
Published
Jul 21, 2026
Tracked Since
Jul 22, 2026