CVE-2026-56742
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.28%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 8.9 HIGHCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
- EPSS
- 0.28% probability · 20th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-862
- Affected
- cilium/cilium
- Source
- security-advisories@github.com
References
- https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333debPatch
- https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857Patch
- https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032bPatch
- https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512caPatch
- https://github.com/cilium/cilium/releases/tag/v1.17.17Release Notes
- https://github.com/cilium/cilium/releases/tag/v1.18.11Release Notes
- https://github.com/cilium/cilium/releases/tag/v1.19.5Release Notes
- https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmjVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.