A flaw was reported [1] in libpurple's SILC protocol plugin, and all software which uses SILC via libpurple. The gmarkupescapetext() function, when called on strings that have not been verified as valid UTF-8, will read past the end of the string and eventually segfault for certain sequences in some versions of Glib2. The behaviour of this function was undefined, and because it depends on the particular version of Glib2 in use, it is unknown what the complete ramifications of the flaw is, however it has been verified that an untrusted user could remotely crash a libpurple client via specially crafted SILC messages.
This flaw is believed to affect all versions of libpurple up to and including 2.10.0. This has been corrected in the upstream git repository [2].
[1] http://developer.pidgin.im/ticket/14636 [2] http://developer.pidgin.im/viewmtn/revision/diff/be5e66abad2af29604bc794cc4c6600ab12751f3/with/7eb1f6d56cc58bbb5b56b7df53955d36b9b419b8
A NULL pointer dereference flaw was found in the way IRC protocol plug-in of the Pidgin multiprotocol instant messaging client processed certain nick names, when list set of users (/who command) was issued upon user session startup and connecting user has had certain encoding configuration setup. A remote attacker could use a specially-crafted string as their nickname to cause the Pidgin client on the side of the victim (connecting user) to crash.
Upstream bug report: [1] http://developer.pidgin.im/ticket/14341
Acknowledgements:
Red Hat would like to thank the Pidgin project for reporting this issue.
libpurple/protocols/irc/msgs.c in the IRC protocol plugin in libpurple in Pidgin before 2.6.2 allows remote IRC servers to cause a denial of service (NULL pointer dereference and application crash) via a TOPIC message that lacks a topic string.
The XMPP protocol plugin in libpurple in Pidgin before 2.6.2 does not properly handle an error IQ stanza during an attempted fetch of a custom smiley, which allows remote attackers to cause a denial of service (application crash) via XHTML-IM content with cid: images.
The msnslpsiprecv function in libpurple/protocols/msn/slp.c in the MSN protocol plugin in libpurple in Pidgin before 2.6.2 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via an SLP invite message that lacks certain required fields, as demonstrated by a malformed message from a KMess client.
The msnslpprocessmsg 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.