CVE-2022-36056
Vulnerabilities with blob verification in sigstore cosign
Cosign is a project under the sigstore organization which aims to make signatures invisible infrastructure. In versions prior to 1.12.0 a number of vulnerabilities have been found in cosign verify-blob, where Cosign would successfully verify an artifact when verification should have failed. First a cosign bundle can be crafted to successfully verify a blob even if the embedded rekorBundle does not reference the given signature. Second, when providing identity flags, the email and issuer of a certificate is not checked when verifying a Rekor bundle, and the GitHub Actions identity is never checked. Third, providing an invalid Rekor bundle without the experimental flag results in a successful verification. And fourth an invalid transparency log entry will result in immediate success for verification. Details and examples of these issues can be seen in the GHSA-8gw7-4j42-w388 advisory linked. Users are advised to upgrade to 1.12.0. There are no known workarounds for these issues.
- Affected
- sigstore · cosign
- CVSS v3.1 NVD
- 5.5 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - EPSS
- 0.15% chance of exploitation in the next 30 days, 4th percentile
- Published
- 2022-09-14
- Updated
- 2025-04-22
Proof-of-concept exploits (1)
Security advisories
- sigstore/cosign/commit/80b79ed8b4d28ccbce3d279fd273606b5cddcc25
- sigstore/cosign/security/advisories/GHSA-8gw7-4j42-w388