fvwm is a highly configurable virtual window manager for X11 desktops. fvwm-menu-directory allows fvwm users to browse directories from within fvwm.
Tavis Ormandy of the Gentoo Linux Security Audit Team discovered that fvwm-menu-directory does not sufficiently sanitise directory names prior to generating menus.
A local attacker who can convince an fvwm-menu-directory user to browse a directory they control could cause fvwm commands to be executed with the privileges of the fvwm user. Fvwm commands can be used to execute arbitrary shell commands.
There is no known workaround at this time.
All fvwm users should upgrade to the latest version:
# emerge --sync # emerge --ask --oneshot --verbose ">=x11-wm/fvwm-2.5.18-r1"