Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-56821
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-29 00:16:38 UTC
Updated2026-07-31 16:17:07 UTC
DescriptionNetty 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 Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.001400000 probability, percentile 0.038310000 (date 2026-08-01)

Problem Types: CWE-299 | CWE-299 CWE-299: Improper Check for Certificate Revocation

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Netty Netty affected < 4.1.136.Final Not specified
CNA Netty Netty affected >= 4.2.0.Final, < 4.2.16.Final Not specified

References

ReferenceSourceLinkTags
github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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