A use-after-free vulnerability in the Linux kernel's net/sched: sch_qfq component can be exploited to achieve local privilege escalation.
When the plug qdisc is used as a class of the qfq qdisc, sending network packets triggers use-after-free in qfqdequeue() due to the incorrect .peek handler of schplug and lack of error checking in agg_dequeue().
We recommend upgrading past commit 8fc134fee27f2263988ae38920bc03da416b03d8.