Mozilla Firefox before 53.0, Firefox ESR before 45.9 or 52.x before 52.1 :- 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 pot ...