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

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). 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
    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

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