Unpatched Argo CD Repo-Server RCE Enables Kubernetes Cluster Takeover

Researchers disclosed an unpatched unauthenticated remote code execution flaw in Argo CD’s repo-server that can be exploited through the gRPC GenerateManifest endpoint when attackers can reach the internal service port. The attack chain abuses Argo CD’s handling of Kustomize options, allowing a crafted request to pass attacker-controlled settings such as --enable-helm and --helm-command so code from a malicious Git repository is executed on the repo-server host.

Synacktiv said it reported the issue to Argo CD maintainers in January 2025, but no patch or CVE had been issued at the time of disclosure. After achieving code execution, the researchers demonstrated theft of the REDIS_PASSWORD environment variable and poisoning of Argo CD’s Redis-backed cache to force deployment of attacker-controlled manifests on the next sync, creating a path to full Kubernetes cluster compromise. The reported mitigation is to enforce Kubernetes network policies that restrict access to repo-server and Redis to trusted Argo CD components, as those protections are not enabled by default in common Helm-based deployments.