Multiple format string vulnerabilities in the ID Software Doom 3 engine, as used by Doom 3 1.3.1 and earlier, Quake 4 1.4.2 and earlier, and Prey 1.3 and earlier, when Punkbuster (PB) is enabled, allow remote attackers to execute arbitrary code or cause a denial of service (daemon crash) via format string specifiers in (1) a PB_Y packet to the YPG server or (2) a PB_U packet to UCON.  NOTE: this issue might be in Punkbuster itself, but there are insufficient details to be certain.