User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the code responsible for parsing SVG path segment objects. The function nsSVGPathSegList::ReplaceItem() does not account for deletion of the segment object list within a user defined DOMAttrModified EventListener. Code within nsSVGPathSegList::ReplaceItem() references the segment list without verifying that it was not deleted in the aforementioned callback. This can be abused to create a dangling reference which can be leveraged to execute arbitrary code within the context of the browser.