CVE-2026-39395

Name	CVE-2026-39395
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
cosign (PTS)	trixie	2.5.0-2	vulnerable
	forky, sid	2.6.2-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
cosign	source	(unstable)	(unfixed)

Notes

https://github.com/sigstore/cosign/security/advisories/GHSA-w6c6-c85g-mmv6
Fixed by: https://github.com/sigstore/cosign/commit/f1ad3ee952313be5d74a49d67ba0aa8d0d5e351f (v3.0.6)
Fixed by: https://github.com/sigstore/cosign/commit/fecddd3c22045a39f52392e71e79f66854b41352 (v2.6.3)