CVE-2026-56743 Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match
Cilium incorrectly allows ingress traffic from the local namespace when using specific NetworkPolicy ipBlock rules with a custom clusterName, bypassing intended network isolation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-56743?
CVE-2026-56743 is a medium-severity missing authorization vulnerability in cilium, published on 15 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-863
Which versions are affected by CVE-2026-56743?
6 open source packages ship an affected version, including github.com/cilium/cilium, cilium and cilium-operator. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cilium/cilium Go | From 1.19.0 | 1.19.5 |
github.com/cilium/cilium Go | From 1.19.0 | 1.19.5 |
github.com/cilium/cilium Go | From 1.19.0 | 1.19.5 |
cilium Bitnami | From 1.19.0 | 1.19.5 |
cilium-operator Bitnami | From 1.19.0 | 1.19.5 |
hubble-relay Bitnami | From 1.19.0 | 1.19.5 |
Products include Cilium Cilium.
How do I fix CVE-2026-56743?
Upgrade github.com/cilium/cilium to 1.19.5 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-56743 being exploited?
There is no known exploitation of CVE-2026-56743 in the wild and no public exploit code.
Other vulnerabilities in cilium
- CVE-2026-49445 Cilium: Sensitive information disclosure and cluster disruption via local Envoy admin socket access
- CVE-2022-29178 Incorrect Default Permissions in Cilium
- CVE-2024-28860 Insecure IPsec transport encryption in Cilium
- CVE-2026-41520 Cillium exposes sensitive information included in the cilium-bugtool debug archive
- CVE-2024-37307 Cilium leaks sensitive information in cilium-bugtool
Sources
Also known as BIT-cilium-2026-56743, BIT-cilium-operator-2026-56743, BIT-hubble-relay-2026-56743, GHSA-fm8w-2m5w-9j7r, GO-2026-6367, MINI-2p8v-pvgj-wc6f and 15 more.