Mozilla Firefox 3.0.5 and earlier 3.0.x versions, when designMode is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a certain (a) replaceChild or (b) removeChild call, followed by a (1) queryCommandValue, (2) queryCommandState, or (3) queryCommandIndeterm call. NOTE: it was later reported that 3.0.6 and 3.0.7 are also affected.
https://www.exploit-db.com/exploits/8219
https://www.exploit-db.com/exploits/8091
https://bugzilla.mozilla.org/show_bug.cgi?id=472507
https://bugzilla.mozilla.org/show_bug.cgi?id=456727
https://bugzilla.mozilla.org/show_bug.cgi?id=448329
http://archives.neohapsis.com/archives/fulldisclosure/2009-01/0224.html
http://archives.neohapsis.com/archives/fulldisclosure/2009-01/0223.html
http://archives.neohapsis.com/archives/fulldisclosure/2009-01/0220.html