xlockmore before 5.43 'dclock' security bypass vulnerability

xlockmore 5.13 allows potential xlock bypass when FVWM switches to the same virtual desktop as a new Gaim window.

xlockmore 5.13 and 5.22 segfaults when using libpam-opensc and returns the underlying xsession. This allows unauthorized users access to the X session.

The (1) checkPasswd and (2) checkGroupXlockPasswds functions in xlockmore before 5.43 do not properly handle when a NULL value is returned upon an error by the crypt or dispcrypt function as implemented in glibc 2.17 and later, which allows attackers to bypass the screen lock via vectors related to invalid salts.