CVE-2026-39395 — Cosign's verify-blob-attestation reports false positive when payload parsing fails

CVE-2026-39395

Cosign's verify-blob-attestation reports false positive when payload parsing fails PUBLISHED

Description (CNA)

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 (CNA)

Vendor / product	Versions
sigstore / cosign	affected >= 3.0.0, < 3.0.6; affected < 2.6.3

CWE

CWE-754

References

https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.