Multiple vulnerabilities in pidgin

Pidgin contains a memory leak in its XML parser when parsing malformed XML. Untrusted XML documents are exchanged in the UPnP and Jabber protocols. Furthermore, the UPnP implementation does not limit the size of the http download. Since the download can be triggered with a UDP packet containing an arbitrary URL, this allows an attacker to
cause Pidgin to download a document of arbitrary size from an any website.

Both vulnerabilities only occur under limited circumstances. Specifically, the UPnP vulnerabilitiy can only be exploited during a small time window during Pidgin's startup sequence. The XML memory leak requires the user to connect to a Jabber server that is either malicious itself or fails to check for malformed XML during forwarding.