An out-of-bounds write in "ClearKeyDecryptor" while decrypting some Clearkey-encrypted media content. The "ClearKeyDecryptor" code runs within the Gecko Media Plugin (GMP) sandbox. If a second mechanism is found to escape the sandbox, this vulnerability allows for the writing of arbitrary data within memory, resulting in a potentially exploitable crash. This vulnerability affects Firefox ESR < 45.9, Firefox ESR < 52.1, and Firefox < 53.
https://www.mozilla.org/security/advisories/mfsa2017-12/
https://www.mozilla.org/security/advisories/mfsa2017-11/
https://www.mozilla.org/security/advisories/mfsa2017-10/
https://www.debian.org/security/2017/dsa-3831
https://bugzilla.mozilla.org/show_bug.cgi?id=1346648
https://access.redhat.com/errata/RHSA-2017:1106
https://access.redhat.com/errata/RHSA-2017:1104