Vulnerability Details CVE-2026-56743
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.002
EPSS Ranking 5.4%
CVSS Severity
CVSS v3 Score 5.4
References
- https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8
- https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171
- https://github.com/cilium/cilium/pull/46305
- https://github.com/cilium/cilium/pull/46456
- https://github.com/cilium/cilium/releases/tag/v1.19.5
- https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r
Products affected by CVE-2026-56743
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cpe:2.3:a:cilium:cilium:1.19.0
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cpe:2.3:a:cilium:cilium:1.19.1
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cpe:2.3:a:cilium:cilium:1.19.2
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cpe:2.3:a:cilium:cilium:1.19.3
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cpe:2.3:a:cilium:cilium:1.19.4