Mozilla Firefox before 3.0.14, and 3.5.x before 3.5.3, does not properly manage pointers for the columns (aka TreeColumns) of a XUL tree element, which allows remote attackers to execute arbitrary code via a crafted HTML document, related to a "dangling pointer vulnerability."
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.