Mozilla Foundation Security Advisory 2016-29

Same-origin policy violation using performance.getEntries and history navigation with session restore

March 8, 2016
Jordi Chancel
Firefox, Firefox ESR
Fixed in
  • Firefox 45
  • Firefox ESR 38.8


Security researcher Jordi Chancel discovered a variant of Mozilla Foundation Security Advisory 2015-136 which was fixed in Firefox 43. In the original bug, it was possible to read cross-origin URLs following a redirect if performance.getEntries() was used along with an iframe to host a page. Navigating back in history through script, content was pulled from the browser cache for the redirected location instead of going to the original location. In the newly reported variant issue, it was found that if a browser session was restored, history navigation would still allow for the same attack as content was restored from the browser cache. This is a same-origin policy violation and could allow for data theft.