Executive Summary
A significant unpatched vulnerability has been disclosed in Argo CD's repo-server component, which lacks authentication for its internal gRPC service. According to researchers at Synacktiv, an attacker capable of reaching the repo-server's internal network port can execute arbitrary commands by submitting crafted requests to the GenerateManifest service. This flaw has reportedly remained unpatched since its initial report in January 2025.
The attack chain involves abusing the 'kustomize' tool's --helm-command option to execute malicious scripts from attacker-controlled repositories. Furthermore, attackers can leverage this access to extract Redis credentials, poison deployment caches, and achieve full cluster takeover. The threat is exacerbated by default configurations in popular Helm charts that disable Kubernetes Network Policies, leaving internal ports exposed to any compromised pod within the cluster.
This discovery highlights a recurring pattern of internal security exposures within Argo CD, following previous vulnerabilities like CVE-2024-31989 and CVE-2025-55190. Organizations are urged to manually enforce network isolation, as no official patch is currently available for this specific RCE vector.