Mozilla developers and community identified and fixed several memory safety bugs in the browser engine used in Firefox and other Mozilla-based products. Some of these bugs showed evidence of memory corruption under certain circumstances, and we presume that with enough effort at least some of these could be exploited to run arbitrary code. These issues only affected Firefox version 40, and were fixed in Firefox version 41. Upstream bug: https://bugzilla.mozilla.org/buglist.cgi?bug_id=1165706,1186657 External References: https://www.mozilla.org/en-US/security/advisories/mfsa2015-96/
Acknowledgements: Red Hat would like to thank the Mozilla project for reporting these issues. Upstream acknowledges Bob Clary and Randell Jesup as the original reporters.