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CVE-2026-56821

Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator

Published: Jul 28, 2026Updated: Aug 7, 2026 Sources: CVE List NVDCWE-299
7.4HIGH
NVD MITRE
EPSS Score
0.1%
Top 96.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

Description

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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. Exploitation can lead to certificate revocation bypass via replay of an expired OCSP response. Any application using OcspServerCertificateValidator is affected; a revoked certificate can be accepted. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-299

Affected Products

netty
oss-projectaka io.netty:netty, netty-incubator-codec-ohttp
nettyLibraryLibrary
OSS Libraries / generic-library

Exploitability

Official Patch Available
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References

https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr
github.com

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