CVE-2026-93858: CWE-78 OS Command Injection in OpenStack Mistral

OpenStack Mistral versions through 23.0.0 contain an OS command injection vulnerability (CWE-78) in the std.ssh_proxied action. The action accepts a proxy_command parameter from an authenticated user and passes it directly to paramiko.ProxyCommand() without sanitization. This causes paramiko to execute the supplied command as a subprocess on the executor host under the executor's service account, regardless of whether the SSH connection succeeds. This allows an authenticated project member to run arbitrary local commands on the executor host, potentially leading to privilege abuse or further compromise. The vulnerability affects versions >=0 <20.1.1, >=21.0.0 <21.0.1, >=22.0.0 <22.0.1, and =23.0.0. The default configuration enabling std.ssh_proxied is affected.

An authenticated project member can execute arbitrary local commands on the executor host with the executor's service account privileges. This can lead to unauthorized command execution, potential privilege escalation, and compromise of the host running Mistral. The vulnerability does not require user interaction beyond authentication and affects the default configuration of Mistral.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider disabling the std.ssh_proxied action if possible to prevent exploitation. Restrict project member permissions to limit exposure. Monitor for unusual command execution activity on executor hosts.