{"id":"CVE-2026-39395","aliases":["BIT-cosign-2026-39395","GHSA-w6c6-c85g-mmv6","GO-2026-5694"],"url":"https://o3.security/vulnerability/CVE-2026-39395","summary":"Cosign's verify-blob-attestation reports false positive when payload parsing fails","details":"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.","published":"2026-04-07T20:06:28.798Z","modified":"2026-07-31T18:31:23.103794178Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/sigstore/cosign","fixedVersion":"3.0.6"},{"ecosystem":"Go","name":"github.com/sigstore/cosign","fixedVersion":"2.6.3"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39395.json"},{"type":"ADVISORY","url":"https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39395"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-31T18:31:23.103794178Z"}}