Auth bypass in Cilium
CVE-2026-26963
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Versions 1.18.0 through 1.18.5 will incorrectly permit traffic from Pods on other nodes when Native Routing, WireGuard and Node Encryption are enabled. This issue has been fixed in version 1.18.6.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (5.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000
Affected products
- Cilium — versions >= 1.18.0, < 1.18.6
Weakness classification (CWE)
References
- github.com/cilium/cilium/security/advisories/GHSA-5r23-prx4-mqg3 (Patch, Vendor Advisory)
- github.com/cilium/cilium/pull/42892 (Issue Tracking)
- github.com/cilium/cilium/commit/88e28e1e62c0b1a02c3f0fc22d888ac9eefbe885 (Patch)
- github.com/cilium/cilium/releases/tag/v1.18.6 (Release Notes)
Frequently asked questions
- What is CVE-2026-26963?
- CVE-2026-26963 is a medium-severity vulnerability in Cilium, classified under Incorrect Authorization. CVSS score: 6.1/10. Published 2026-02-20.
- How severe is CVE-2026-26963?
- Medium severity. CVSS v3 base score is 6.1 out of 10.