The block subsystem in the Linux kernel before 5.2 has a use-after-free that can lead to arbitrary code execution in the kernel context and privilege escalation. This is related to blk_mq_free_rqs and blk_cleanup_queue.
Reference and upstream patch:
Created kernel tracking bugs for this issue:
Affects: fedora-all [bug 1961293]
This was fixed for Fedora with the 5.2 stable kernel rebases.