GHSA-g27r-r6ph-vf5r
sequoia-git has broken hard revocation handling
Blast Radius
sequoia-gitReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Before sq-git checks if a commit can be authenticated, it first looks for hard revocations. Because parsing a policy is expensive
and a project's policy rarely changes, sq-git has an optimization to only check a policy if it hasn't checked it before. It does this by maintaining a set of policies that it had already seen keyed on the policy's hash. Unfortunately, due to a bug the hash was truncated to be 0 bytes and thus only hard revocations in the target commit were considered. Normally this is not a problem as hard revocations are not removed from the signing policy.
An attacker could nevertheless exploit this flaw as follows. Consider Alice and Bob who maintain a project together. If Bob's
certificate is compromised and Bob issues a hard revocation, Alice can add it to the project's signing policy. An attacker who has
access to Bob's key can then create a merge request that strips the hard revocation. If Alice merges Bob's merge request, then
the latest commit will not carry the hard revocation, and sq-git will not see the hard revocation when authenticating that commit or any following commits.
Note: for this attack to be successful, Alice needs to be tricked into merging the malicious MR. If Alice is reviewing MRs, then she is likely to notice changes to the signing policy.
Reported-by: Hassan Sheet
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | sequoia-git | all versions | 0.6.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sequoia-git. 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 sequoia-git to 0.6.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g27r-r6ph-vf5r 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-g27r-r6ph-vf5r 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-g27r-r6ph-vf5r. 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-g27r-r6ph-vf5r in your dependencies?
O3 detects GHSA-g27r-r6ph-vf5r across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.