CVE-2025-23028: DoS in Cilium agent DNS proxy from crafted DNS responses
In a Kubernetes cluster where Cilium is configured to proxy DNS traffic, an attacker can crash Cilium agents by sending a crafted DNS response to workloads from outside the cluster.
For traffic that is allowed but without using DNS-based policy, the dataplane will continue to pass traffic as configured at the time of the DoS. For workloads that have DNS-based policy configured, existing connections may continue to operate, and new connections made without relying on DNS resolution may continue to be established, but new connections which rely on DNS resolution may be disrupted. Any configuration changes that affect the impacted agent may not be applied until the agent is able to restart.
References
- github.com/advisories/GHSA-9m5p-c77c-f9j7
- github.com/cilium/cilium
- github.com/cilium/cilium/commit/1971bc684b6b36703ebae0dd7539c623f988a257
- github.com/cilium/cilium/commit/b1948e217a4212b81175d8bf763d0ef350fcc96c
- github.com/cilium/cilium/pull/36252
- github.com/cilium/cilium/security/advisories/GHSA-9m5p-c77c-f9j7
- nvd.nist.gov/vuln/detail/CVE-2025-23028
Detect and mitigate CVE-2025-23028 with GitLab Dependency Scanning
Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Learn more about Dependency Scanning →