GHSA-24qp-4xx8-3jvj

### Impact

For Cilium users who: - Use Gateway API for Ingress for some services **AND** - Use [LB-IPAM](https://docs.cilium.io/en/stable/network/lb-ipam/) or BGP for LB Service implementation **AND** - Use network policies to block egress traffic from workloads in a namespace to workloads in other namespaces

Egress traffic from workloads covered by such network policies to LoadBalancers configured by `Gateway` resources will incorrectly be allowed.

LoadBalancer resources not deployed via a Gateway API configuration are not affected by this issue.

### Patches

This issue was fixed by https://github.com/cilium/proxy/pull/1172.

This issue affects:

- Cilium v1.15 between v1.15.0 and v1.15.14 inclusive - Cilium v1.16 between v1.16.0 and v1.16.7 inclusive - Cilium v1.17 between v1.17.0 and v1.17.1 inclusive

This issue is fixed in:

- Cilium v1.15.15 - Cilium v1.16.8 - Cilium v1.17.2

### Workarounds

A Clusterwide Cilium Network Policy can be used to work around this issue for users who are unable to upgrade. An outline of such a policy is provided below:

``` apiVersion: "cilium.io/v2" kind: CiliumClusterwideNetworkPolicy metadata: name: "workaround" spec: endpointSelector: matchExpressions: - key: reserved:ingress operator: Exists ingress: - fromEntities: - world ```

- The policy opens up connectivity from all locations outside the cluster into the Cilium Ingress Gateway. - The policy establishes a default deny for all other traffic towards the Cilium Ingress Gateway, including all in-cluster sources. - It is possible to tailor the policy to more narrowly allow inbound traffic while creating a default deny posture for traffic between namespaces. Users should edit the policy to bring it in line with the security requirements particular to their environments.

### Acknowledgements

The Cilium community has worked together with members of the Isovalent team to prepare these mitigations. Special thanks to @jrajahalme for the fix.

### For more information

If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.