One of the critical vulnerabilities opens users up to cross-site scripting attacks because the browser did not run proper security checks, Mozilla said in its security advisory.
The flaw “allows for cross-site scripting attacks through web pages and Firefox extensions. The fix enables the Script Security Manager to force security checks on all frame scripts”, Mozilla explained.
Other critical flaws fixed in Firefox 10 include: crash with malformed embedded XSLT stylesheets, potential memory corruption when decoding Off Vorbis files, child nodes from nsDOMAttribute still accessible after removal of nodes, and a miscellaneous category of memory safety hazards.
Under the miscellaneous category, Mozilla explained that its developers “identified and fixed several memory safety bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these bugs showed evidence of memory corruption under certain circumstances, and we presume that with enough effort at least some of these could be exploited to run arbitrary code.”
Further, Mozilla improved Firefox add-on compatibility and simplified the update process for all users.