CVE-2023-27593
MEDIUMcilium-agent container can access the host via `hostPath` mount
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
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.11.15, 1.12.8, and 1.13.1, an attacker with access to a Cilium agent pod can write to /opt/cni/bin due to a hostPath mount of that directory in the agent pod. By replacing the CNI binary with their own malicious binary and waiting for the creation of a new pod on the node, the attacker can gain access to the underlying node.
The issue has been fixed and the fix is available on versions 1.11.15, 1.12.8, and 1.13.1. Some workarounds are available. Kubernetes RBAC should be used to deny users and service accounts exec access to Cilium agent pods. In cases where a user requires exec access to Cilium agent pods, but should not have access to the underlying node, no workaround is possible.
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 CVE-2023-27593 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 CVE-2023-27593 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 CVE-2023-27593. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-27593 in your dependencies?
O3 detects CVE-2023-27593 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.