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Ubuntu Security Notice USN-1273-1
November 21, 2011

pidgin vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 11.04
- Ubuntu 10.10
- Ubuntu 10.04 LTS

Summary:

Pidgin could be made to crash if it received specially crafted network
traffic.

Software Description:
- pidgin: multi-protocol instant messaging client

Details:

Marius Wachtler discovered that Pidgin incorrectly handled malformed YMSG
messages in the Yahoo! protocol handler. A remote attacker could send a
specially crafted message and cause Pidgin to crash, leading to a denial
of service. This issue only affected Ubuntu 10.04 LTS and 10.10.
(CVE-2011-1091)

Marius Wachtler discovered that Pidgin incorrectly handled HTTP 100
responses in the MSN protocol handler. A remote attacker could send a
specially crafted message and cause Pidgin to crash, leading to a denial
of service. (CVE-2011-3184)

Diego Bauche Madero discovered that Pidgin incorrectly handled UTF-8
sequences in the SILC protocol handler. A remote attacker could send a
specially crafted message and cause Pidgin to crash, leading to a denial
of service.  (CVE-2011-3594)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 11.04:
  pidgin                          1:2.7.11-1ubuntu2.1

Ubuntu 10.10:
  pidgin                          1:2.7.3-1ubuntu3.3

Ubuntu 10.04 LTS:
  pidgin                          1:2.6.6-1ubuntu4.4

After a standard system update you need to restart Pidgin to make
all the necessary changes.

References:
  http://www.ubuntu.com/usn/usn-1273-1
  CVE-2011-1091, CVE-2011-3184, CVE-2011-3594

Package Information:
  https://launchpad.net/ubuntu/+source/pidgin/1:2.7.11-1ubuntu2.1
  https://launchpad.net/ubuntu/+source/pidgin/1:2.7.3-1ubuntu3.3
  https://launchpad.net/ubuntu/+source/pidgin/1:2.6.6-1ubuntu4.4