Mozilla: Out-of-bounds read when HTTP/2 DATA frames are sent with incorrect data (MFSA 2017-11, MFSA 2017-12)

An out-of-bounds read when an HTTP/2 connection to a servers sends "DATA" frames with incorrect data content. This leads to a potentially exploitable crash. This vulnerability affects Thunderbird 52.1, Firefox ESR 45.9, Firefox ESR 52.1, and Firefox 53...