Cilium host policy bypass in endpoint-routes mode with dual-stackGHSA-wc5v-r48v-g4vh
LOWFix: cilium/cilium@c758da7GHSA-wc5v-r48v-g4vh is a low-severity (CVSS 3.3) vulnerability in github.com/cilium/cilium. A fix is available for github.com/cilium/cilium — see the affected versions and patch details below.
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
This vulnerability allows bypassing host policies for IPv6 traffic coming from a Cilium-managed pod and destined to the host-network namespace (e.g., to a host-network pod). Host policy enforcement on IPv4 or for traffic coming from outside the node is not affected.
Cilium is only affected by this vulnerability if IPv4, IPv6, endpoint routes, and the host firewall are enabled. Note that endpoint routes are typically only enabled in GKE, EKS, AKS, and OpenShift; in those environments, IPv6 is typically disabled. Host firewall is disabled by default.
Patches
The bug is fixed in versions v1.10.13 and v1.11.7 of Cilium.
Workarounds
For affected users who can't upgrade, one potential workaround is to ensure all pods have network policies that prevent sending arbitrary traffic to the local node.
References
Commit fixing the vulnerability: https://github.com/cilium/cilium/commit/c758da7e9d19cd19b96dc90424c0b5ec7409cd0a.
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 | 1.10.13go get github.com/cilium/cilium@v1.10.13 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.11.0&&< 1.11.7 | 1.11.7go get github.com/cilium/cilium@v1.11.7 |
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 1.10.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-wc5v-r48v-g4vh 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.
Frequently Asked Questions
Is GHSA-wc5v-r48v-g4vh in your dependencies?
Find it across Go, including transitive dependencies.