CVE-2026-56821

{"id": "CVE-2026-56821", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-56821", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-07-30T03:55:19.093244Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.4, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.2}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "netty", "product": "netty", "versions": [{"status": "affected", "version": "< 4.1.136.Final"}, {"status": "affected", "version": ">= 4.2.0.Final, < 4.2.16.Final"}]}]}], "published": "2026-07-29T00:16:38.573", "references": [{"url": "https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr", "source": "security-advisories@github.com"}, {"url": "https://github.com/netty/netty/security/advisories/GHSA-g7hg-vrcf-mvmr", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Undergoing Analysis", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-299"}]}], "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 Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator flags an out-of-date OCSP response but does not stop processing it, so an expired GOOD response is still reported as VALID, letting an on-path attacker replay a stale GOOD response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."}], "lastModified": "2026-07-31T16:17:07.983", "sourceIdentifier": "security-advisories@github.com"}