CVE-2026-56821: Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator
Affected: netty · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 12% of scored CVEs
DescriptionCVE.org
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 Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- netty · netty< 4.1.136.Final; >= 4.2.0.Final, < 4.2.16.Final
On the Atlas
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-56821 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.