Many open source advocates like to crow about how Microsoft users must patch-and-patch to fix security holes, while we go merrily on, bulletproof.
Most of the problems have to do with how Linux handles graphics.
SUSE owners could become zombies and launch DDOS attacks by getting a specific Acrobat document. Red Hat owners could crash their machines by opening malicious TIFF files. Mandrakesoft also has exploitable problems involving graphic files.
You might want to lock the door while you install these patches, folks. You don't want to hear your Windows-using friends tut-tutting in the background.