Firefox 3.6.4 has been released, this version address 7 vulnerabilities which range from critical issues such as denial of service or arbitrary code execution bugs along with a few lower level issues. Below is list of critical vulnerabilities fixed in this version
MFSA 2010-30 Integer Overflow in XSLT Node Sorting
MFSA 2010-29 Heap buffer overflow in nsGenericDOMDataNode::SetTextInternal
MFSA 2010-28 Freed object reuse across plugin instances
MFSA 2010-26 Crashes with evidence of memory corruption (rv:1.9.2.4/ 1.9.1.10)
For full list of fixed vulnerabilities click here.
In this version they have also improved the handling of plugin crashes, now if a plugin crash or freez while visiting or browsing a website it will now crash the plugin without killing the browser (process end). User and reader if you have not update visit below link to download.