Network Policies & (Clusterwide) Cilium Network Policies with namespace label selectors may unexpectedly select pods with maliciously crafted labelsGHSA-pfhr-pccp-hwmh
MEDIUMGHSA-pfhr-pccp-hwmh is a medium-severity (CVSS 4.3) 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/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
If a user has Network Policies with namespace selectors selecting labels of namespaces, or (clusterwide) Cilium Network Policies matching on namespace labels, then it is possible for an attacker with Kubernetes pod deploy rights (either directly or indirectly via higher-level APIs such as Deployment, Daemonset etc) to craft additional pod labels such that the pod is selected by another policy that exists rather than the expected policy.
Patches
The problem has been fixed and is available on versions >=1.10.14, >=1.11.8, >=1.12.1
Workarounds
There are no workarounds available.
Acknowledgements
The Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to Sander Mathijssen for not only highlighting the issue but also proposing a resolution.
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 | 1.10.14go get github.com/cilium/cilium@v1.10.14 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.11.0&&< 1.11.8 | 1.11.8go get github.com/cilium/cilium@v1.11.8 |
| 🐹Go | github.com/cilium/cilium | ≥ 1.12.0&&< 1.12.1 | 1.12.1go get github.com/cilium/cilium@v1.12.1 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cilium/cilium to 1.10.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-pfhr-pccp-hwmh 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-pfhr-pccp-hwmh in your dependencies?
Find it across Go, including transitive dependencies.