Auth bypass in Cilium
CVE-2026-53935
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.9 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (25.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Cilium — versions < 1.17.16, >= 1.18.2, < 1.18.10, >= 1.19.0, < 1.19.4
Weakness classification (CWE)
References
- github.com/cilium/cilium/security/advisories/GHSA-q6h5-q3q6-f87x
- github.com/cilium/cilium/pull/45412
- github.com/cilium/cilium/pull/45584
- github.com/cilium/cilium/pull/45585
- github.com/cilium/cilium/commit/81d446395673dc2c684c047c12715caffac1a351
- github.com/cilium/cilium/commit/92ca32eda85aa0c7611c28221cc26fa08be17ebc
- github.com/cilium/cilium/commit/fe7eb53c7aac9fa7ec610b1975d73fbbb198c66d
Frequently asked questions
- What is CVE-2026-53935?
- CVE-2026-53935 is a medium-severity vulnerability in Cilium, classified under Incorrect Authorization. CVSS score: 6.9/10. Published 2026-07-07.
- How severe is CVE-2026-53935?
- Medium severity. CVSS v3 base score is 6.9 out of 10.