GHSA-4c4x-jm2x-pf9j
MEDIUMGHSA-4c4x-jm2x-pf9j is a medium-severity (CVSS 5.3) Server-Side Request Forgery (SSRF) vulnerability in github.com/sigstore/rekor. O3 Security confirms whether GHSA-4c4x-jm2x-pf9j is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Rekor affected by Server-Side Request Forgery (SSRF) via provided public key URL
Blast Radius
github.com/sigstore/rekorReal-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
/api/v1/index/retrieve supports retrieving a public key via a user-provided URL, allowing attackers to trigger SSRF to arbitrary internal services.
Since the SSRF only can trigger GET requests, the request cannot mutate state. The response from the GET request is not returned to the caller so data exfiltration is not possible. A malicious actor could attempt to probe an internal network through Blind SSRF.
Impact
- SSRF to cloud metadata (169.254.169.254)
- SSRF to internal Kubernetes APIs
- SSRF to any service accessible from Fulcio's network
Patches
Upgrade to v1.5.0. Note that this is a breaking change to the search API and fully disables lookups by URL. If you require this feature, please reach out and we can discuss alternatives.
Workarounds
Disable the search endpoint with --enable_retrieve_api=false.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/sigstore/rekor | all versions | 1.5.0 |
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/rekor. 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/rekor to 1.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4c4x-jm2x-pf9j 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-4c4x-jm2x-pf9j 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-4c4x-jm2x-pf9j. 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-4c4x-jm2x-pf9j in your dependencies?
O3 detects GHSA-4c4x-jm2x-pf9j across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.