client/cl_parse.c in the id3 Quake 3 Engine 1.32c and the Icculus Quake 3 Engine (ioquake3) revision 810 and earlier allows remote malicious servers to overwrite arbitrary write-protected cvars variables on the client, such as cl_allowdownload for Automatic Downloading and fs_homepath for the quake3 path, via a string of cvar names and values sent from the server. NOTE: this can be combined with another vulnerability to overwrite arbitrary files.

The Automatic Downloading option in the id3 Quake 3 Engine and the Icculus Quake 3 Engine (ioquake3) before revision 804 allows remote attackers to overwrite arbitrary files in the quake3 directory (fs_homepath cvar) via a long string of filenames, as contained in the neededpaks buffer.