# CVE-2026-26963: Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled

Source: https://junglewise.ai/threats/cve-2026-26963-cilium-may-not-enforce-host-firewall-policies-when-native-routing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-23  
License: CC BY 4.0 with a link back

CVE-2026-26963 · Severity: low · CVSS 3.1 · Published 2026-02-23

Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled in github.com/cilium/cilium

Technologies: [github.com/cilium/cilium (Go)](https://junglewise.ai/threats/technologies/github-com-cilium-cilium). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-26963 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-26963 being exploited in the wild.

**How severe is CVE-2026-26963?** Low severity, with a CVSS score of 3.1, published 23 February 2026.

**Which products and versions are affected?** github.com/cilium/cilium (Go) SEMVER:introduced=1.18.0,fixed=1.18.6.

**Is there a fix for CVE-2026-26963?** Yes. github.com/cilium/cilium (Go): upgrade to 1.18.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-26963?** Check whether you run github.com/cilium/cilium (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/cilium/cilium (Go): upgrade to 1.18.6 or later

  ```sh
  go get github.com/cilium/cilium@v1.18.6
  ```


## Affected products

- github.com/cilium/cilium (Go) SEMVER:introduced=1.18.0,fixed=1.18.6

## Identifiers

- CVE-2026-26963
- GHSA-5r23-prx4-mqg3
- GO-2026-4522

## Related threats

- [Cilium incorrect authorization in Kubernetes NetworkPolicy ipBlock rules](https://junglewise.ai/threats/cve-2026-56743-cilium-incorrect-authorization-in-kubernetes-networkpolicy)
- [Cilium authorization bypass in Gateway API HTTPRoute mirroring](https://junglewise.ai/threats/cve-2026-56742-cilium-authorization-bypass-in-gateway-api-httproute-mirroring)
- [Cilium world-accessible Envoy admin socket on cluster nodes](https://junglewise.ai/threats/cve-2026-49445-cilium-world-accessible-envoy-admin-socket-on-cluster-nodes)
- [Cilium traffic hijacking via CiliumLocalRedirectPolicy addressMatcher](https://junglewise.ai/threats/cve-2026-53935-cilium-traffic-hijacking-via-ciliumlocalredirectpolicy)
- [Cilium sensitive information disclosure in cilium-bugtool](https://junglewise.ai/threats/cve-2026-41520-cilium-sensitive-information-disclosure-in-cilium-bugtool)