CVE-2026-56743
Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium5.4 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.4 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.25% · top 84% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.
Weakness
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Gogithub.com/cilium/ciliumGHSA-fm8w-2m5w-9j7r (opens in a new tab)
References (6)
- https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r (opens in a new tab)x_refsource_CONFIRM
- https://github.com/cilium/cilium/pull/46305 (opens in a new tab)x_refsource_MISC
- https://github.com/cilium/cilium/pull/46456 (opens in a new tab)x_refsource_MISC
- https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8 (opens in a new tab)x_refsource_MISC
- https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171 (opens in a new tab)x_refsource_MISC
- https://github.com/cilium/cilium/releases/tag/v1.19.5 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-fm8w-2m5w-9j7r (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-56743)Record last updated .