High CVSS 8.9
CVE-2026-56742
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.
What this means
- Exposure
- Exploitable from the adjacent network, with an ordinary user account and with no action from the victim.
- Impact
- An attacker can read sensitive data, modify or destroy data and degrade the service. The impact spreads beyond the vulnerable component into other parts of the system.
- Weakness
- No authorisation check happens before the action.
- Likelihood
- Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.
What to doFold into the next patch cycle.
Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.