Vulnerability Instance

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.