An out of bounds read error occurs when parsing some HTTP digest authorization responses, resulting in information leakage through the reading of random memory containing matches to specifically set patterns. This vulnerability affects Firefox < 52 and Thunderbird < 52.
https://www.mozilla.org/security/advisories/mfsa2017-09/
https://www.mozilla.org/security/advisories/mfsa2017-05/
https://bugzilla.mozilla.org/show_bug.cgi?id=1338876