The Broken Link Checker WordPress plugin before 2.4.12 does not limit which query variables it accepts from user input on sites using plain permalinks, allowing unauthenticated users to overwrite arbitrary PHP global variables, and to execute arbitrary code on the server when a classic (non-block) is active.

The Broken Link Checker WordPress plugin before 2.4.12 does not limit which query variables it accepts from user input on sites using plain permalinks, allowing unauthenticated users to overwrite arbitrary PHP global variables, and to execute arbitrary code on the server when a classic (non-block) is active.