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

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.