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
EPSS: 0.001 (2.7th percentile) — read the EPSS interpretation.
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.
Affected products
- Cilium — versions >= 1.18.0, < 1.18.6
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, 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.