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.
This flaw requires a malicious MSN server to actually crash the pidgin client.
Also upstream has confirmed that this is crash only and remote code execution is not possible.
Closing this as not a security flaw.
Red Hat does not consider this to be a security flaw. As a malicious MSN server is needed, there are far worlse implications to a user connecting to an untrusted server than a DoS.