GHSA-37cx-329c-33x3
MEDIUMgo-git improperly verifies data integrity values for .idx and .pack files
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/go-git/go-git/v5Real-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
A vulnerability was discovered in go-git whereby data integrity values for .pack and .idx files were not properly verified. This resulted in go-git potentially consuming corrupted files, which would likely result in unexpected errors such as object not found.
For context, clients fetch packfiles from upstream Git servers. Those files contain a checksum of their contents, so that clients can perform integrity checks before consuming it. The pack indexes (.idx) are generated locally by go-git, or the git cli, when new .pack files are received and processed. The integrity checks for both files were not being verified correctly.
Note that the lack of verification of the packfile checksum has no impact on the trust relationship between the client and server, which is enforced based on the protocol being used (e.g. TLS in the case of https:// or known hosts for ssh://). In other words, the packfile checksum verification does not provide any security benefits when connecting to a malicious or compromised Git server.
Patches
Users should upgrade to v5.16.5, or the latest v6 pseudo-version, in order to mitigate this vulnerability.
Workarounds
In case updating to a fixed version of go-git is not possible, users can run git fsck from the git cli to check for data corruption on a given repository.
Credit
Thanks @N0zoM1z0 for finding and reporting this issue privately to the go-git project.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/go-git/go-git/v5 | all versions | 5.16.5 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/go-git/go-git/v5. 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/go-git/go-git/v5 to 5.16.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-37cx-329c-33x3 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-37cx-329c-33x3 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-37cx-329c-33x3. 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-37cx-329c-33x3 in your dependencies?
O3 detects GHSA-37cx-329c-33x3 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.