CVE-2026-56820
Published:July 21, 2026
Updated:August 04, 2026
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.
Affected Packages
https://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.1.100.Final <netty-4.1.136.FinalFix Suggestion:
Update to version netty-4.1.136.Finalhttps://github.com/netty/netty.git (GITHUB):
Affected version(s) >=netty-4.2.0.Final <netty-4.2.16.FinalFix Suggestion:
Update to version netty-4.2.16.Finalio.netty:netty-handler-ssl-ocsp (JAVA):
Affected version(s) >=4.1.86.Final <4.1.136.FinalFix Suggestion:
Update to version 4.1.136.Finalio.netty:netty-handler-ssl-ocsp (JAVA):
Affected version(s) >=4.1.86.Final <4.1.136.FinalFix Suggestion:
Update to version 4.1.136.Finalio.netty:netty-handler-ssl-ocsp (JAVA):
Affected version(s) >=4.2.0.Final <4.2.16.FinalFix Suggestion:
Update to version 4.2.16.FinalRelated Resources (8)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.1
Attack Vector
NETWORK
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.4
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Certificate Validation
EPSS
Base Score:
0.18