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Vulnerability · Published Jul 15, 2026 · Assigned by GitHub_M

CVE-2026-56742Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces

Medium 5.9

In plain English

A medium-severity missing authorization in cilium from cilium. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.2%top 92.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/cilium/cilium1.17.17GHSA-w7c2-w76w-5hmj
Gogithub.com/cilium/cilium1.19.5GHSA-w7c2-w76w-5hmj
Gogithub.com/cilium/cilium1.17.17, 1.18.11, 1.19.5GO-2026-6596
Gogithub.com/cilium/ciliumCilium1.18.11GHSA-w7c2-w76w-5hmj

Affected products (as reported)

VendorProductVersions
cilium cilium < 1.17.17>= 1.18.0, < 1.18.11>= 1.19.0, < 1.19.5

Weakness: CWE-862 · Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L

References