Cilium is a networking, observability, and security solution with an eBPF-based dataplane. In version 1.13.0, when Cilium is started, there is a short period when Cilium eBPF programs are not attached to the host. During this period, the host does not implement any of Cilium's featureset. This can cause disruption to newly established connections during this period due to the lack of Load Balancing, or can cause Network Policy bypass due to the lack of Network Policy enforcement during the window. This vulnerability impacts any Cilium-managed endpoints on the node (such as Kubernetes Pods), as well as the host network namespace (including Host Firewall). This vulnerability is fixed in Cilium 1.13.1 or later. Cilium releases 1.12.x, 1.11.x, and earlier are not affected. There are no known workarounds.

`cilium-cli` is the command line interface to install, manage, and troubleshoot Kubernetes clusters running Cilium. Prior to version 0.13.2,`cilium-cli`, when used to configure cluster mesh functionality, can remove the enforcement of user permissions on the `etcd` store used to mirror local cluster information to remote clusters. Users who have set up cluster meshes using the Cilium Helm chart are not affected by this issue. Due to an incorrect mount point specification, the settings specified by the `initContainer` that configures `etcd` users and their permissions are overwritten when using `cilium-cli` to configure a cluster mesh. An attacker who has already gained access to a valid key and certificate for an `etcd` cluster compromised in this manner could then modify state in that `etcd` cluster. This issue is patched in `cilium-cli` 0.13.2. As a workaround, one may use Cilium's Helm charts to create their cluster.

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. For users with the following configuration: 1. An allow policy that selects a Layer 3 destination and a port range `AND` 2. A Layer 7 allow policy that selects a specific port within the first policy's range the Layer 7 enforcement would not occur for the traffic selected by the Layer 7 policy. This issue only affects users who use Cilium's port range functionality, which was introduced in Cilium v1.16. This issue is patched in PR #35150. This issue affects Cilium v1.16 between v1.16.0 and v1.16.3 inclusive. This issue is patched in Cilium v1.16.4. Users are advised to upgrade. Users with network policies that match the pattern described above can work around the issue by rewriting any policies that use port ranges to individually specify the ports permitted for traffic.