CVE-2026-53935 CiliumLocalRedirectPolicy addressMatcher allows cross-namespace service traffic hijacking and can break service translation
Users with policy creation rights can hijack cross-namespace service traffic or disrupt service translation by specifying arbitrary ClusterIPs in CiliumLocalRedirectPolicies.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53935?
CVE-2026-53935 is a medium-severity missing authorization vulnerability in cilium, published on 7 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Cilium is a networking, observability, and security solution. Prior to 1.17.16, from 1.18.2 to 1.18.9, and from 1.19.0 to 1.19.3, users with the ability to create CiliumLocalRedirectPolicies can specify arbitrary ClusterIPs via addressMatcher, enabling hijacking traffic to Services in any namespace and bypassing namespace scoping enforced by serviceMatcher; deleting such a policy can also corrupt Cilium internal service state and stop service translation for the affected Service. This issue is fixed in versions 1.17.16, 1.18.10, and 1.19.4.
Weakness: CWE-863
Which versions are affected by CVE-2026-53935?
10 open source packages ship an affected version, including github.com/cilium/cilium, cilium and cilium-operator.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cilium/cilium Go | All versions | 1.17.16, 1.18.10, 1.19.4 |
github.com/cilium/cilium Go | All versions | 1.17.16 |
github.com/cilium/cilium Go | All versions | 1.17.16 |
github.com/cilium/cilium Go | From 1.18.2 | 1.18.10 |
github.com/cilium/cilium Go | From 1.18.2 | 1.18.10 |
github.com/cilium/cilium Go | From 1.19.0 | 1.19.4 |
4 more packages
github.com/cilium/cilium Go | From 1.19.0 | 1.19.4 |
cilium Bitnami | All versions | 1.17.16, 1.18.10, 1.19.4 |
cilium-operator Bitnami | All versions | 1.17.16, 1.18.10, 1.19.4 |
hubble-relay Bitnami | All versions | 1.17.16, 1.18.10, 1.19.4 |
How do I fix CVE-2026-53935?
Upgrade github.com/cilium/cilium to a fixed version for your release line: 1.17.16, 1.18.10 or 1.19.4.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-53935 being exploited?
There is no known exploitation of CVE-2026-53935 in the wild and no public exploit code.
Sources
Also known as BIT-cilium-2026-53935, BIT-cilium-operator-2026-53935, BIT-hubble-relay-2026-53935, GHSA-q6h5-q3q6-f87x, GO-2026-5914, MINI-2cx6-r5r6-w4j5 and 27 more.