The XMPP protocol plugin in libpurple in Pidgin before 2.10.8 does not properly determine whether the from address in an iq reply is consistent with the to address in an iq request, which allows remote attackers to spoof iq traffic or cause a denial of service (NULL pointer dereference and application crash) via a crafted reply.

The Yahoo! protocol plugin in libpurple in Pidgin before 2.10.8 does not properly validate UTF-8 data, which allows remote attackers to cause a denial of service (application crash) via crafted byte sequences.

gtkimhtml.c in Pidgin before 2.10.8 does not properly interact with underlying library support for wide Pango layouts, which allows user-assisted remote attackers to cause a denial of service (application crash) via a long URL that is examined with a tooltip.

The pidgin_conv_chat_rename_user function in gtkconv.c in Pidgin before 2.10.2 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) by changing a nickname while in an XMPP chat room.

The msn_oim_report_to_user function in oim.c in the MSN protocol plugin in libpurple in Pidgin before 2.10.2 allows remote servers to cause a denial of service (application crash) via an OIM message that lacks UTF-8 encoding.

family_feedbag.c in the oscar protocol plugin in libpurple in Pidgin before 2.10.1 does not perform the expected UTF-8 validation on message data, which allows remote attackers to cause a denial of service (application crash) via a crafted (1) AIM or (2) ICQ message associated with buddy-list addition.

The silc_channel_message function in ops.c in the SILC protocol plugin in libpurple in Pidgin before 2.10.1 does not perform the expected UTF-8 validation on message data, which allows remote attackers to cause a denial of service (application crash) via a crafted message, a different vulnerability than CVE-2011-3594.

The XMPP protocol plugin in libpurple in Pidgin before 2.10.1 does not properly handle missing fields in (1) voice-chat and (2) video-chat stanzas, which allows remote attackers to cause a denial of service (application crash) via a crafted message.

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.