Quake 2 server 3.13 on Linux does not properly check file permissions for the config.cfg configuration file, which allows local users to read arbitrary files via a symlink from config.cfg to the target file.

Quake 2 server allows remote attackers to cause a denial of service via a spoofed UDP packet with a source address of 127.0.0.1, which causes the server to attempt to connect to itself.

Quake 2 (Q2) server 3.20 and 3.21 allows remote attackers to obtain sensitive server cvar variables, obtain directory listings, and execute Q2 server admin commands via a client that does not expand "$" macros, which causes the server to expand the macros and leak the information, as demonstrated using "say $rcon_password."