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.

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.

Quake II server before R1Q2, as used in multiple products, allows remote attackers to corrupt the server's client state data structure by exiting a session without a valid disconnect command, then reconnecting, which prevents a mod from being notified of changes in the client state. NOTE: the impact of this issue will vary depending on which mod is being used.