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Mozilla Foundation Security Advisory 2015-129

Certain escaped characters in host of Location-header are being treated as non-escaped

Announced
November 3, 2015
Reporter
Frans Rosén
Impact
Low
Products
Firefox
Fixed in
  • Firefox 42

Description

Security researcher Frans Rosén reported that URLs with certain escaped characters in hostnames are parsed incorrectly. This leads to parsing being abandoned when an effected escaped character is encountered followed by a navigation to the previously parsed version of the URL. When combined with a site allowing for navigation redirection that allows for escaped characters, this could lead to potential extraction of site specific tokens.

References