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CVE PROGRAM SOURCE RECORD4.3 Medium

CVE-2026-39395

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

sigstore cosign

  • >= 3.0.0, < 3.0.6affected
  • < 2.6.3affected

References