GHSA-w6c6-c85g-mmv6
Cosign's verify-blob-attestation reports false positive when payload parsing fails
En bref
- Publiée
- Mise à jour
- CVE
- CVE-2026-39395
- Alias
- BIT-cosign-2026-39395, GO-2026-5694
- CVSS_V3
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
Description
## Description `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. ## Impact When `cosign verify-blob-attestation` is used without `--check-claims` set to `true`, an attestation that has a valid signature but a malformed or unparsable payload would be incorrectly validated. Additionally, systems relying on `--type <predicate type>` to reject attestations with mismatched types would be lead to trust the unexpected attestation type. ## Patches v3.0.6, v2.6.3 ## Workarounds Always set `--check-claims=true` for attestation verification.
Paquets affectés
| Paquet | Versions |
|---|---|
| Go · github.com/sigstore/cosign | introduced 3.0.0, fixed 3.0.6 |
| Go · github.com/sigstore/cosign | introduced 0, fixed 2.6.3 |
Références
- https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6 WEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-39395 ADVISORY
- https://github.com/sigstore/cosign PACKAGE
Sources
| Source | Licence |
|---|---|
| OSV.dev | CC-BY 4.0 — GitHub Advisory Database |