CVE-2022-36056
MEDIUMVulnerabilities with blob verification in sigstore cosign
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/sigstore/cosignReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sigstore/cosign | all versions | 1.12.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/sigstore/cosign. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/sigstore/cosign to 1.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-36056 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2022-36056 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2022-36056. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2022-36056 in your dependencies?
O3 detects CVE-2022-36056 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.