CVE-2026-39395GHSA-W6C6-C85G-MMV6BIT-COSIGN-2026-39395GO-2026-5694
Cosign's verify-blob-attestation reports false positive when payload parsing fails
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.0.6, 2.6.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- sigstore cosign
From 3.0.0 · fixed in 3.0.6; fixed in 2.6.3
- github.com/sigstore/cosignGo
From 3.0.0 · fixed in 3.0.6
- github.com/sigstore/cosignGo
fixed in 2.6.3
- github.com/sigstore/cosignGo
All versions
- github.com/sigstore/cosign/v2Go
fixed in 2.6.3
- github.com/sigstore/cosign/v3Go
From 3.0.0 · fixed in 3.0.6