Off-by-one error in the GeoIP module in the AMX Mod X 1.76d plugin for Half-Life Server might allow attackers to execute arbitrary code or cause a denial of service via unspecified input related to geolocation, which triggers an error message from the (1) geoip_code2 or (2) geoip_code3 function, leading to a buffer overflow.
Cross-site scripting (XSS) vulnerability in auth.w in djeyl.net WebMod 0.48 Half-Life Dedicated Server plugin allows remote attackers to inject arbitrary web script or HTML via the redir parameter.
Half-Life Server 1.1.1.0 and earlier allows remote attackers to cause a denial of service (resource exhaustion) via multiple responses to the initial challenge with different cd_key values, which reaches the player limit and prevents other players from connecting until the original responses have timed out.
Format string vulnerability in Half Life dedicated server build 3104 and earlier allows remote attackers to execute arbitrary commands by injecting format strings into the changelevel command, via the system console or rcon.