GHSA-h34r-jxqm-qgpr
MEDIUMjuju/utils leaks private key in certs
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/juju/utils/v4/certReal-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
Summary
Certs generated by v4 contain their private key.
Details
Background
Recently, I encountered an API in Go that’s easy to misuse: sha512.Sum384 and sha512.New384().Sum look very similar and behave very differently. https://go.dev/play/p/kDCqqoYk84k demonstrates this. I want to discuss extending static analysis to detect this case with the go community, but before I do that, I want to make a best-effort pass at open-source projects to fix the existing bugs. I figured that if there were any vulnerabilities out there, they would be easy to find once that discussion begins, so it’s better to address them early.
This work is a hobby project and has no affiliation with my employer, so I may be slow to respond due to existing commitments.
PoC
https://go.dev/play/p/vSW0U3Hq4qk
Impact
This code (cert.NewLeaf) generates certs with the SubjectKeyId set to sha512.New384().Sum(/* private */ key).
If a cert which was generated by cert.NewLeaf is transferred over the network in plaintext, as is often the case in TLS handshakes, an attacker listening on that network may sniff the cert and trivially extract the private key from it. This applies to client and server TLS certs generated by vulnerable versions of this library.
Getting the server cert and its key would only require performing a TLS handshake (with a matching SNI) with the server. At that point, the attacker could impersonate the server.
Similarly, getting the client cert and its key would require getting the client to perform a TLS handshake against an attacker-controlled server. At that point, an attacker could impersonate the client.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/juju/utils/v4/cert | all versions | 4.0.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/juju/utils/v4/cert. 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/juju/utils/v4/cert to 4.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h34r-jxqm-qgpr 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-h34r-jxqm-qgpr 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-h34r-jxqm-qgpr. 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-h34r-jxqm-qgpr in your dependencies?
O3 detects GHSA-h34r-jxqm-qgpr across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.