{"id":"CVE-2026-56821","state":"PUBLISHED","title":"Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator","description":"Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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.","publishedAt":"2026-07-28T23:07:13.616Z","updatedAt":"2026-07-31T16:12:56.878Z","severity":{"score":7.4,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["netty netty"],"affected":[{"vendor":"netty","product":"netty","versions":[{"version":"< 4.1.136.Final","status":"affected"},{"version":">= 4.2.0.Final, < 4.2.16.Final","status":"affected"}]}],"references":["https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr"],"weaknesses":["CWE-299"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56821.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56821","state":"PUBLISHED","datePublished":"2026-07-28T23:07:13.616Z","dateUpdated":"2026-07-31T16:12:56.878Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-23T14:55:09.116Z"},"containers":{"cna":{"title":"Netty: Out-of-date OCSP Responses Accepted by OcspServerCertificateValidator","descriptions":[{"lang":"en","value":"Netty is an asynchronous, event-driven network application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 Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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":[{"vendor":"netty","product":"netty","versions":[{"version":"< 4.1.136.Final","status":"affected"},{"version":">= 4.2.0.Final, < 4.2.16.Final","status":"affected"}]}],"references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr","name":"https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.4,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-299","lang":"en","description":"CWE-299: Improper Check for Certificate Revocation","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-29T17:32:19.753Z"},"source":{"advisory":"GHSA-g7hg-vrcf-mvmr","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-30T03:55:19.093244Z","id":"CVE-2026-56821","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-31T16:12:56.878Z"}}]}}}