The IRC protocol plugin in libpurple in Pidgin before 2.10.8 does not validate argument counts, which allows remote IRC servers to cause a denial of service (application crash) via a crafted message.

The SIMPLE protocol functionality in Pidgin before 2.10.8 allows remote attackers to have an unspecified impact via a negative Content-Length header, which triggers a buffer overflow.

Integer signedness error in the MXit functionality in Pidgin before 2.10.8 allows remote attackers to cause a denial of service (segmentation fault) via a crafted emoticon value, which triggers an integer overflow and a buffer overflow.

libpurple/protocols/yahoo/libymsg.c in Pidgin before 2.10.8 allows remote attackers to cause a denial of service (crash) via a Yahoo! P2P message with a crafted length field, which triggers a buffer over-read.

Integer overflow in libpurple/protocols/gg/lib/http.c in the Gadu-Gadu (gg) parser in Pidgin before 2.10.8 allows remote attackers to have an unspecified impact via a large Content-Length value, which triggers a buffer overflow.

The STUN protocol implementation in libpurple in Pidgin before 2.10.8 allows remote STUN servers to cause a denial of service (out-of-bounds write operation and application crash) by triggering a socket read error.

Pidgin before 2.10.8 allows remote MSN servers to cause a denial of service (NULL pointer dereference and crash) via a crafted (1) SOAP response, (2) OIM XML response, or (3) Content-Length header.

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.

gtkutils.c in Pidgin before 2.10.8 on Windows allows user-assisted remote attackers to execute arbitrary programs via a message containing a file: URL that is improperly handled during construction of an explorer.exe command. NOTE: this vulnerability exists because of an incomplete fix for CVE-2011-3185.

Buffer overflow in util.c in libpurple in Pidgin before 2.10.8 allows remote HTTP servers to cause a denial of service (application crash) or possibly have unspecified other impact via an invalid chunk-size field in chunked transfer-coding data.

util.c in libpurple in Pidgin before 2.10.8 does not properly allocate memory for HTTP responses that are inconsistent with the Content-Length header, which allows remote HTTP servers to cause a denial of service (application crash) via a crafted response.

Multiple integer signedness errors in libpurple in Pidgin before 2.10.8 allow remote attackers to cause a denial of service (application crash) via a crafted timestamp value in an XMPP message.

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.

libpurple in Finch in Pidgin before 2.6.6, when an XMPP multi-user chat (MUC) room is used, does not properly parse nicknames containing <br> sequences, which allows remote attackers to cause a denial of service (application crash) via a crafted nickname.

gtkimhtml.c in Pidgin before 2.6.6 allows remote attackers to cause a denial of service (CPU consumption and application hang) by sending many smileys in a (1) IM or (2) chat.

Pierre Noguès found a NULL pointer dereference in the Pidgin MSN SLP protocol implementation, by processing custom emoticon messages. A remote, authenticated user could use this deficiency to cause a denial of service (Pidgin crash).

Acknowledgements:

Red Hat would like to thank the Pidgin project for reporting this issue. Upstream acknowledges Pierre Noguès of Meta Security as the original reporter.

Pidgin 2.13.0 contains a denial of service vulnerability that allows local attackers to crash the application by providing an excessively long username string during account creation. Attackers can input a buffer of 1000 characters in the username field and trigger a crash when joining a chat, causing the application to become unavailable.

An exploitable out-of-bounds read exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT contact information sent from the server can result in memory disclosure.

A buffer overflow vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent from the server could potentially result in arbitrary code execution. A malicious server or an attacker who intercepts the network traffic can send an invalid size for a packet which will trigger a buffer overflow.

A NULL pointer dereference vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in a denial of service vulnerability. A malicious server can send a packet starting with a NULL byte triggering the vulnerability.

A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in an out-of-bounds read. A malicious server or user can send an invalid mood to trigger this vulnerability.

An out-of-bounds write vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could cause memory corruption resulting in code execution.

A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in a null pointer dereference. A malicious server or an attacker who intercepts the network traffic can send invalid data to trigger this vulnerability and cause a crash.

An exploitable memory corruption vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT MultiMX message sent via the server can result in an out-of-bounds write leading to memory disclosure and code execution.

A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in an out-of-bounds read. A malicious server or an attacker who intercepts the network traffic can send invalid data to trigger this vulnerability and cause a crash.

An information leak exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in an out-of-bounds read. A malicious user, server, or man-in-the-middle can send an invalid size for an avatar which will trigger an out-of-bounds read vulnerability. This could result in a denial of service or copy data from memory to the file, resulting in an information leak if the avatar is sent to another user.

Multiple memory corruption vulnerabilities exist in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could result in multiple buffer overflows, potentially resulting in code execution or memory disclosure.

A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent from the server could potentially result in an out-of-bounds read. A malicious server or man-in-the-middle attacker can send invalid data to trigger this vulnerability.

A buffer overflow vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent by the server could potentially result in an out-of-bounds write of one byte. A malicious server can send a negative content-length in response to a HTTP request triggering the vulnerability.

An information leak exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent to the server could potentially result in an out-of-bounds read. A user could be convinced to enter a particular string which would then get converted incorrectly and could lead to a potential out-of-bounds read.