Multiple vulnerabilities have been reported in Mozilla Firefox
Mozilla Firefox 21.x
These vulnerabilities can be exploited by malicious people to conduct cross-site scripting and spoofing attacks, disclose potentially sensitive information, bypass certain security restrictions, and compromise a user's system.
Secunia Advisory SA53970
Secunia Advisory SA53953
Mozilla Advisory mfsa2013-49
Mozilla Advisory mfsa2013-50
Mozilla Advisory mfsa2013-51
Mozilla Advisory mfsa2013-53
Mozilla Advisory mfsa2013-55
Mozilla Advisory mfsa2013-56
Mozilla Advisory mfsa2013-59
1) An error within Profiler can be exploited to execute arbitrary code.
2) An error when handling a frame element within a sandboxed iframe can be exploited to bypass the intended restrictions.
3) An error when handling the X-Frame-Options header related to the server push in multi-part responses can be exploited to conduct clickjacking attacks.
4) An error when handling the "getUserMedia" permission dialog for an iframe can be exploited to display the origin of the top-level document and conduct spoofing attacks.
5) Some unspecified errors can be exploited to cause memory corruption. No further information is currently available.
Cross Site Scripting
Exposure of sensitive information
Vendor recommends updating to current version