The pidginconvchatrenameuser 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 silcchannelmessage 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.
familyfeedbag.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 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.
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.
A flaw was found in the handling of HTTP 100 responses in the MSN protocol plugin. It can cause the application to attempt to access memory that it does not have access to. This only affects users who have turned on the HTTP connection method for their accounts (it's off by default). This might only be triggerable by a malicious server and not a malicious peer. Remote code execution is not possible.
Reference: http://pidgin.im/news/security/?id=54
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.
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.
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.
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.
msg.c in the MSN protocol plugin in libpurple in Pidgin before 2.10.4 does not properly handle crafted characters, which allows remote servers to cause a denial of service (application crash) by placing these characters in a text/plain message.
The msnoimreporttouser 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.
sametime.c in the Sametime protocol plugin in libpurple in Pidgin before 2.10.7 does not properly terminate long user IDs, which allows remote servers to cause a denial of service (application crash) via a crafted packet.
The MXit protocol plugin in libpurple in Pidgin before 2.10.7 might allow remote attackers to create or overwrite files via a crafted (1) mxit or (2) mxit/imagestrips pathname.
upnp.c in libpurple in Pidgin before 2.10.7 does not properly terminate long strings in UPnP responses, which allows remote attackers to cause a denial of service (application crash) by leveraging access to the local network.
Buffer overflow in http.c in the MXit protocol plugin in libpurple in Pidgin before 2.10.7 allows remote servers to execute arbitrary code via a long HTTP header.