CVE-2026-56821

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 Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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.

CVSS v3 7.4 HIGH

7.4^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr	Exploit Vendor Advisory
https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr	Exploit Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:netty:netty::::::::
	cpe:2.3:a:netty:netty::::::::

History

No history.

Information

Published : 2026-07-29 00:16

Updated : 2026-08-07 15:05

NVD link : CVE-2026-56821

Mitre link : CVE-2026-56821

CVE.ORG link : CVE-2026-56821

JSON object : View

Products Affected

netty

netty

CWE

CWE-299

Improper Check for Certificate Revocation

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