I see three crash stacks like this: 0 js::CompartmentChecker::fail js/src/jscntxtinlines.h:204 1 JS_GetGlobalForObject js/src/jsapi.cpp:2233 2 mozilla::dom::URLBinding::revokeObjectURL obj-firefox/dom/bindings/URLBinding.cpp:268 3 js::InvokeKernel js/src/jsinterp.cpp:389 4 js::Interpret js/src/jsinterp.cpp:2348 5 js::RunScript I'm not sure exactly what is calling JS_GetGlobalForObject, as the line numbers don't seem to match what I have locally. https://crash-stats.mozilla.com/report/index/896e519b-6b03-424b-be5a-156902130107 https://crash-stats.mozilla.com/report/index/7a896715-fdf0-452a-8682-a95362130102 https://crash-stats.mozilla.com/report/index/bdb83485-e593-44bb-9577-555762130102 URL was converted to the new DOM bindings in bug 792675, which is in 19. Speculatively marking 19 and later as affected.
The build ID for those three crashes is "20121214030827". Bug 821760 landed on m-c on 2012-12-15. So as far as I can tell, this is a duplicate of that bug.