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.
Debian Security Advisory 1741-1 - Jesus Olmos Gonzalez discovered that an integer overflow in the PSI Jabber client may lead to remote denial of service.