CVE-2026-56743
Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match
- State
- Published
- Severity
- 5.4 Medium
- Published
- Jul 15, 2026
- Updated
- Jul 16, 2026
- Reserved
- Jun 22, 2026
Description
Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.4 Medium | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N | GitHub_M |
Weaknesses
- CWE-863 Incorrect Authorization
Affected Products
| Product | Versions |
|---|---|
ciliumcilium |
|
References
- https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r
- https://github.com/cilium/cilium/pull/46305
- https://github.com/cilium/cilium/pull/46456
- https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8
- https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171
- https://github.com/cilium/cilium/releases/tag/v1.19.5
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