CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCVE-2026-39395
Medium (5.3) in sigstore cosign. EPSS 0.2% chance of exploitation in the next 30 days. Fixed in github.com/sigstore/cosign 2.6.3, 3.0.6.
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.
Severity
- EPSS
- 0.2% chance of exploitation in the next 30 days; higher than 15% of CVEs (scores of 2026-10-31)
- CWE
- CWE-754
- Published
- Modified
- Record from
- the NVD, synced
Affected
- sigstore:cosign
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-w6c6-c85g-mmv6 | Go | github.com/sigstore/cosign | >=3.0.0 <3.0.6 | 3.0.6 |
| GHSA-w6c6-c85g-mmv6 | Go | github.com/sigstore/cosign | <2.6.3 | 2.6.3 |
| GO-2026-5694 | Go | github.com/sigstore/cosign | all versions | no fix published |
| GO-2026-5694 | Go | github.com/sigstore/cosign/v2 | <2.6.3 | 2.6.3 |
| GO-2026-5694 | Go | github.com/sigstore/cosign/v3 | >=3.0.0 <3.0.6 | 3.0.6 |