GHSA-8fg8-jh2h-f2hc
MEDIUMPotential network policy bypass when routing IPv6 traffic
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/cilium/cilium🐹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
Under specific conditions, Cilium may misattribute the source IP address of traffic to a cluster, identifying external traffic as coming from the host on which Cilium is running. As a consequence, network policies for that cluster might be bypassed, depending on the specific network policies enabled. Only IPv6 traffic is impacted by this vulnerability.
This issue only manifests when:
- Cilium is routing IPv6 traffic, and
- Kube-proxy is used for service handling, and
- NodePorts are used to route traffic to pods.
IPv6 is disabled by default. Cilium's kube-proxy replacement feature is not affected by this vulnerability.
Patches
The problem has been fixed and is available on versions >=1.11.15, >=1.12.8, >=1.13.1
Workarounds
Disable IPv6 routing (IPv6 is disabled by default).
Acknowledgements
The Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to Yusuke Suzuki for both highlighting and fixing the issue.
For more information
If you have any questions or comments about this advisory, please reach out on Slack.
As usual, if you think you found a related vulnerability, we strongly encourage you to report security vulnerabilities to our private security mailing list: [email protected] - first, before disclosing them in any public forums. This is a private mailing list where only members of the Cilium internal security team are subscribed to, and is treated as top priority.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/cilium/cilium | all versions | 1.11.15 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.12.0&&< 1.12.8 | 1.12.8 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.13.0&&< 1.13.1 | 1.13.1 |
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. 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/cilium/cilium to 1.11.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8fg8-jh2h-f2hc 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-8fg8-jh2h-f2hc 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-8fg8-jh2h-f2hc. 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-8fg8-jh2h-f2hc in your dependencies?
O3 detects GHSA-8fg8-jh2h-f2hc across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.