CVE-2026-55797: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in argoproj argo-cd

CVE-2026-55797 is an OS command injection vulnerability in Argo CD's repo-server affecting versions from 2.11.0 through 2.14.21, 3.0.0 through before 3.3.15, 3.4.0 through before 3.4.10, 3.5.0 through before 3.5.4, and exactly 3.6.0-rc1. The vulnerability arises because the proxy host and port in an SSH ProxyCommand are executed through a shell without proper neutralization of shell metacharacters. This allows a user who can create or update repository or repository credential templates to supply a crafted proxy host string that leads to arbitrary command execution on the repo-server. Successful exploitation can lead to full compromise of Git, Helm, and OCI credentials stored or used by the repo-server. The vendor has fixed the issue in versions 3.3.15, 3.4.10, 3.5.4, and 3.6.0-rc2.

An attacker with repository or credential template creation or update privileges can execute arbitrary OS commands on the Argo CD repo-server. This can lead to full compromise of sensitive credentials used for Git, Helm, and OCI repositories, potentially allowing further unauthorized access or code execution within the Kubernetes environment managed by Argo CD. The CVSS v3.1 score of 8.8 reflects high impact on confidentiality, integrity, and availability.

Upgrade Argo CD to one of the fixed versions: 3.3.15, 3.4.10, 3.5.4, or 3.6.0-rc2. These versions contain an official fix that properly neutralizes shell metacharacters in the SSH ProxyCommand, preventing command injection. Until upgrading, restrict permissions to create or update repository or repository credential templates to trusted users only.