{"id":"CVE-2026-39395","state":"PUBLISHED","title":"Cosign's verify-blob-attestation reports false positive when payload parsing fails","description":"Cosign provides code signing and transparency for containers and binaries. Prior to 3.0.6 and 2.6.3, cosign verify-blob-attestation may erroneously report a \"Verified OK\" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. This vulnerability is fixed in 3.0.6 and 2.6.3.","publishedAt":"2026-04-07T20:06:28.798Z","updatedAt":"2026-04-08T15:49:16.587Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["sigstore cosign"],"affected":[{"vendor":"sigstore","product":"cosign","versions":[{"version":">= 3.0.0, < 3.0.6","status":"affected"},{"version":"< 2.6.3","status":"affected"}]}],"references":["https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6"],"weaknesses":["CWE-754"],"ingestedAt":"2026-10-29T20:11:50.837Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/39xxx/CVE-2026-39395.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-39395","state":"PUBLISHED","datePublished":"2026-04-07T20:06:28.798Z","dateUpdated":"2026-04-08T15:49:16.587Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-06T22:06:40.516Z"},"containers":{"cna":{"title":"Cosign's verify-blob-attestation reports false positive when payload parsing fails","descriptions":[{"lang":"en","value":"Cosign provides code signing and transparency for containers and binaries. Prior to 3.0.6 and 2.6.3, cosign verify-blob-attestation may erroneously report a \"Verified OK\" result for attestations with malformed payloads or mismatched predicate types. For old-format bundles and detached signatures, this was due to a logic flaw in the error handling of the predicate type validation. For new-format bundles, the predicate type validation was bypassed completely. This vulnerability is fixed in 3.0.6 and 2.6.3."}],"affected":[{"vendor":"sigstore","product":"cosign","versions":[{"version":">= 3.0.0, < 3.0.6","status":"affected"},{"version":"< 2.6.3","status":"affected"}]}],"references":[{"url":"https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6","name":"https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-754","lang":"en","description":"CWE-754: Improper Check for Unusual or Exceptional Conditions","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-04-07T20:06:28.798Z"},"source":{"advisory":"GHSA-w6c6-c85g-mmv6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-08T15:49:08.895545Z","id":"CVE-2026-39395","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-08T15:49:16.587Z"}}]}}}