GHSA-vwf8-q6fw-4wcm is a medium-severity (CVSS 5.4) Information Exposure vulnerability in github.com/cilium/cilium. A fix is available for github.com/cilium/cilium — see the affected versions and patch details below.
Cilium leaks information via incorrect ReferenceGrant update logic in Gateway API
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-vwf8-q6fw-4wcm.
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.
How urgent is this, really
GHSA-vwf8-q6fw-4wcm plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/cilium/cilium🐹github.com/cilium/ciliumReal-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
Due to ReferenceGrant changes not being immediately propagated in Cilium's GatewayAPI controller, Gateway resources are able to access secrets in other namespaces after the associated ReferenceGrant has been revoked. This can lead to Gateways continuing to establish sessions using secrets that they should no longer have access to.
Patches
This issue was resolved in https://github.com/cilium/cilium/pull/34032.
This issue affects:
- Cilium v1.15 between v1.15.0 and v1.15.7 inclusive
- Cilium v1.16.0
This issue has been patched in:
- Cilium v1.15.8
- Cilium v1.16.1
Workarounds
Any modification of a related Gateway/HTTPRoute/GRPCRoute/TCPRoute CRD (for example, adding any label to any of these resources) will trigger a reconciliation of ReferenceGrants on an affected cluster.
Acknowledgements
The Cilium community has worked together with members of Cure53 and Isovalent to prepare these mitigations. Special thanks to @sayboras for resolving this issue.
For more information
If you have any questions or comments about this advisory, please reach out on Slack.
If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [email protected]. This is a private mailing list for the Cilium security team, and your report will be treated as top priority.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/cilium/cilium | ≥ 1.16.0&&< 1.16.1 | 1.16.1go get github.com/cilium/cilium@v1.16.1 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.15.0&&< 1.15.8 | 1.15.8go get github.com/cilium/cilium@v1.15.8 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cilium/cilium, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cilium/cilium to 1.16.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vwf8-q6fw-4wcm 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-vwf8-q6fw-4wcm can be triaged on real exposure rather than presence alone.
Tailored to GHSA-vwf8-q6fw-4wcm. 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-vwf8-q6fw-4wcm in your dependencies?
O3 Security finds GHSA-vwf8-q6fw-4wcm across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.