Watchguard XCS 9.2 and 10.0 before build 150522 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the id parameter to ADMIN/mailqueue.spl.
The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.