CVE-2026-56742
Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces
8.9
HIGH
CVSS 3.1
EPSS 0.17%
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.
How to fix CVE-2026-56742
To remediate CVE-2026-56742, upgrade the affected package to a fixed version below.
- —upgrade to 1.17.17 or later
- —upgrade to 1.17.17 or later
- —upgrade to 1.17.17 or later
Is CVE-2026-56742 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.17.17, >= 1.18.0, < 1.18.11, >= 1.19.0, < 1.19.5
- from 0, < 1.17.17, >= 1.18.0, < 1.18.11, >= 1.19.0, < 1.19.5
- from 0, < 1.17.17, >= 1.18.0, < 1.18.11, >= 1.19.0, < 1.19.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.9 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L |
References (9)
- WEBgithub.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb
- WEBgithub.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857
- WEBgithub.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b
- WEBgithub.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca