medium5.9
CVE-2026-56742
Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces
Impact
Cilium is a networking, observability, and security solution. Prior to 1.17.17, 1.18.11, and 1.19.5, Cilium clusters using Gateway API allow users with permissions to create or update namespaced HTTPRoutes to mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism. Gateway API functionality is disabled by default. This issue is fixed in versions 1.17.17, 1.18.11, and 1.19.5.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| go | github.com/cilium/cilium | < 1.17.17 | 1.17.17 |
| go | github.com/cilium/ciliumCilium | >= 1.18.0, < 1.18.11 | 1.18.11 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Cilium | Cilium | before 1.17.17 from 1.18.0 before 1.18.11 from 1.19.0 before 1.19.5 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-w7c2-w76w-5hmj
- https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmj
- https://nvd.nist.gov/vuln/detail/CVE-2026-56742
- https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb
- https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857
- https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b
- https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca
- https://github.com/cilium/cilium/releases/tag/v1.17.17
- https://github.com/cilium/cilium/releases/tag/v1.18.11
- https://github.com/cilium/cilium/releases/tag/v1.19.5