CVE 2008-6393
PSI Jabber client before 0.12.1 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a file transfer request with a negative value in a SOCKS5 option, which bypasses a signed integer check and triggers an integer overflow and a heap-based buffer overflow.
See the 
CVE page on Mitre.org
for more details.
