Mozilla Firefox 3.6.x before 3.6.3 does not properly manage the scopes of DOM nodes that are moved from one document to another, which allows remote attackers to conduct use-after-free attacks and execute arbitrary code via unspecified vectors involving improper interaction with garbage collection, as demonstrated by Nils during a Pwn2Own competition at CanSecWest 2010.
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.