source: http://www.securityfocus.com/bid/8299/info
 
Half-Life Client has been reported prone to a remotely exploitable buffer overflow condition.
 
The issue presents itself in the client connection routine, used by the client to negotiate a connection to the Half-Life game server. Due to a lack of sufficient bounds checking performed on both the parameter and value of data transmitted from the game server to the client, a malicious server may execute arbitrary code on an affected client.

https://github.com/offensive-security/exploit-database-bin-sploits/raw/master/bin-sploits/22967.zip