The msn_httpconn_parse_data function in httpconn.c in the MSN protocol plugin in libpurple in Pidgin before 2.10.0 does not properly handle HTTP 100 responses, which allows remote attackers to cause a denial of service (incorrect memory access and application crash) via vectors involving a crafted server message.
Credit:
The information has been provided by Marius Wachtler.
Incorrect handling of HTTP 100 responses in the MSN protocol plugin 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. We believe remote code execution is not possible.
Vendor Status:
Pidgin had issued an update for this vulnerability