xscreensaver authentication bypass

XScreenSaver 4.10, when using a remote directory service for credentials, does not properly handle the results from the getpwuid function in drivers/lock.c when there is no network connectivity, which causes XScreenSaver to crash and unlock the screen and allows local users to bypass authentication.

xscreensaver 5.03 and earlier, when running without xscreensaver-gl-extras (GL extras) installed, crashes when /usr/bin/xscreensaver-gl-helper does not exist and a user attempts to unlock the screen, which allows attackers with physical access to gain access to the locked session.

Xscreensaver 4.14 contains certain debugging code that should have been omitted, which causes Xscreensaver to create temporary files insecurely in the (1) apple2, (2) xanalogtv, and (3) pong screensavers, and allows local users to overwrite arbitrary files via a symlink attack.

security flaw

Xscreensaver before 4.15 creates temporary files insecurely in (1) driver/passwd-kerberos.c, (2) driver/xscreensaver-getimage-video, (3) driver/xscreensaver.kss.in, and the (4) vidwhacker and (5) webcollage screensavers, which allows local users to overwrite arbitrary files via a symlink attack.

security flaw

rdesktop 1.3.1 with xscreensaver 4.14, and possibly other versions, when running on Fedora and possibly other platforms, does not release the keyboard focus when xscreensaver starts, which causes the password to be entered into the active window when the user unlocks the screen.