proxy.c in libpurple in Pidgin before 2.10.4 does not properly handle canceled SOCKS5 connection attempts, which allows user-assisted remote authenticated users to cause a denial of service (application crash) via a sequence of XMPP file-transfer requests.

The g_markup_escape_text function in the SILC protocol plug-in in libpurple 2.10.0 and earlier, as used in Pidgin and possibly other products, allows remote attackers to cause a denial of service (crash) via invalid UTF-8 sequences that trigger use of invalid pointers and an out-of-bounds read, related to interactions with certain versions of glib2.

The irc_msg_who function in msgs.c in the IRC protocol plugin in libpurple 2.8.0 through 2.9.0 in Pidgin before 2.10.0 does not properly validate characters in nicknames, which allows user-assisted remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted nickname that is not properly handled in a WHO response.

The msn_httpconn_parse_data function in httpconn.c in the MSN protocol plugin in libpurple in Pidgin before 2.10.0 does not properly handle HTTP 100 responses, which allows remote attackers to cause a denial of service (incorrect memory access and application crash) via vectors involving a crafted server message.

gtkutils.c in Pidgin before 2.10.0 on Windows allows user-assisted remote attackers to execute arbitrary programs via a file: URL in a message.

libymsg.c in the Yahoo! protocol plugin in libpurple in Pidgin 2.6.0 through 2.7.10 allows (1) remote authenticated users to cause a denial of service (NULL pointer dereference and application crash) via a malformed YMSG notification packet, and allows (2) remote Yahoo! servers to cause a denial of service (NULL pointer dereference and application crash) via a malformed YMSG SMS message.

directconn.c in the MSN protocol plugin in libpurple 2.7.6 through 2.7.8 in Pidgin before 2.7.9 allows remote authenticated users to cause a denial of service (NULL pointer dereference and application crash) via a short p2pv2 packet in a DirectConnect (aka direct connection) session.

libpurple in Pidgin before 2.7.4 does not properly validate the return value of the purple_base64_decode function, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and application crash) via a crafted message, related to the plugins for MSN, MySpaceIM, XMPP, and Yahoo! and the NTLM authentication support.

The clientautoresp function in family_icbm.c in the oscar protocol plugin in libpurple in Pidgin before 2.7.2 allows remote authenticated users to cause a denial of service (NULL pointer dereference and application crash) via an X-Status message that lacks the expected end tag for a (1) desc or (2) title element.