Firefox just released version 19.0.2 only to address a security issue.
Title: Use-after-free in HTML Editor
Impact: Critical
Announced: March 7, 2013
Description
VUPEN Security, via TippingPoint's Zero Day Initiative, reported a use-after-free within the HTML editor when content script is run by the document.execCommand() function while internal editor operations are occurring. This could allow for arbitrary code execution.