Security researcher Looben Yang reported a mechanism where the Clients API in Service Workers can be used to trigger an out-of-bounds read in ServiceWorkerManager. This results in a potentially exploitable crash. External Reference: https://www.mozilla.org/security/announce/2016/mfsa2016-22.html Acknowledgements: Name: the Mozilla project Upstream: Looben Yang Statement: This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5, 6 and 7.