CVE-2026-55797: Argo CD repo-server command injection via crafted SSH repository SOCKS5 proxy URL

Argo CD runs a shell command in the repo-server when it clones or fetches an SSH Git repository that has a proxy URL. The proxy host and port are copied into an SSH ProxyCommand. A host that contains shell metacharacters breaks out of that command and runs in the repo-server.

All versions from v2.11.0 onward are affected, including every currently supported release. v2.10.20 and earlier are not. The behavior was introduced in 9b27aeb1a4 (2024-01-09, #15864), the change that added SOCKS5 proxy support for SSH Git URLs, and was first released in v2.11.0.

The repository must use SSH. http, https, and socks5 proxy URLs all take this path when they are set on an SSH repository. An HTTPS Git repository uses the proxy as an HTTP proxy and does not build this command.

Anyone who can create or update a repository or a repository credential template can set the proxy. That includes a project-scoped repository permission, argocd repo add --proxy, and a repository Secret. A credential template applies its proxy to every matching SSH repository that does not have its own credentials. Argo CD runs the command when it tests the repository connection and on later fetches. The process can read other Git, Helm, and OCI credentials stored for the repo-server.