{"id":"BIT-cosign-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.","aliases":["CVE-2026-39395","GHSA-w6c6-c85g-mmv6","GO-2026-5694"],"modified":"2026-09-08T08:45:30.513685045Z","published":"2026-04-09T08:37:13.235Z","database_specific":{"severity":"Medium","cpes":["cpe:2.3:a:sigstore:cosign:*:*:*:*:*:go:*:*"]},"references":[{"type":"ADVISORY","url":"https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-39395"}],"affected":[{"package":{"name":"cosign","ecosystem":"Bitnami","purl":"pkg:bitnami/cosign"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.6.3"},{"introduced":"3.0.0"},{"fixed":"3.0.6"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/cosign/BIT-cosign-2026-39395.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"}]}],"schema_version":"1.9.0"}