GHSA-9vcr-p3rj-q5q6
MEDIUMsigstore-go has a multi-log threshold bypass via single compromised log
Blast Radius
github.com/sigstore/sigstore-goReal-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
Impact
What kind of vulnerability is it? Who is impacted?
A verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) expected defense-in-depth against the compromise of a single log instance. However, threshold counting counted verified witnesses per-entry or per-validation-path rather than per-log-authority.
As a result, a single compromised transparency log could forge multiple entries with different indices, and a single compromised CT log could verify multiple times (either across multiple certificate chains or via multiple embedded SCTs), fully satisfying the multi-log threshold requirements and defeating the multi-log policy.
Note that this does not affect Cosign, as Cosign sets a threshold of 1.
Patches
Has the problem been patched? What versions should users upgrade to?
Upgrade to v1.1.5.
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
There is no workaround, beyond relying on trusted logs.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sigstore/sigstore-go | all versions | 1.2.0 |
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/sigstore-go. 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/sigstore-go to 1.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9vcr-p3rj-q5q6 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 GHSA-9vcr-p3rj-q5q6 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 GHSA-9vcr-p3rj-q5q6. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9vcr-p3rj-q5q6 in your dependencies?
O3 detects GHSA-9vcr-p3rj-q5q6 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.