The msn_slp_process_msg function in libpurple/protocols/msn/slpcall.c in the MSN protocol plugin in libpurple 2.6.0 and 2.6.1, as used in Pidgin before 2.6.2, allows remote attackers to cause a denial of service (application crash) via a handwritten (aka Ink) message, related to an uninitialized variable and the incorrect "UTF16-LE" charset name.

The msn_slplink_process_msg function in libpurple/protocols/msn/slplink.c in libpurple, as used in Pidgin (formerly Gaim) before 2.5.9 and Adium 1.3.5 and earlier, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) by sending multiple crafted SLP (aka MSNSLP) messages to trigger an overwrite of an arbitrary memory location. NOTE: this issue reportedly exists because of an incomplete fix for CVE-2009-1376.

The OSCAR protocol implementation in Pidgin before 2.5.8 misinterprets the ICQWebMessage message type as the ICQSMS message type, which allows remote attackers to cause a denial of service (application crash) via a crafted ICQ web message that triggers allocation of a large amount of memory.