Security researcher Abhishek Arya (Inferno) of the Google Chrome Security Team used the Address Sanitizer tool to discover an access violation due to uninitialized data during Extensible Stylesheet Language Transformation (XSLT) processing. This leads to a potentially exploitable crash.
In general this flaw cannot be exploited through email in the Thunderbird and Seamonkey products because scripting is disabled, but is potentially a risk in browser or browser-like contexts.