Improper Check for Certificate Revocation Affecting io.netty:netty-handler-ssl-ocsp package, versions [,4.1.136.Final)[4.2.0.Final,4.2.16.Final)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-IONETTY-18233130
- published23 Jul 2026
- disclosed22 Jul 2026
- creditVioleta Georgieva
Introduced: 22 Jul 2026
NewCVE-2026-56821 (opens in a new tab)How to fix?
Upgrade io.netty:netty-handler-ssl-ocsp to version 4.1.136.Final, 4.2.16.Final or higher.
Overview
io.netty:netty-handler-ssl-ocsp is a Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients.
Affected versions of this package are vulnerable to Improper Check for Certificate Revocation in the OcspServerCertificateValidator. An attacker can cause a revoked certificate to be accepted by replaying an expired OCSP response.