A use-after-free vulnerability can occur in the compositor during certain graphics operations when a raw pointer is used instead of a reference counted one. This results in a potentially exploitable crash.
External References:
https://www.mozilla.org/en-US/security/advisories/mfsa2018-10/
Statement:
Red Hat Enterprise Linux 5 is now in Extended Life Phase of the support and maintenance life cycle. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.