A use-after-free vulnerability has been resolved in the Linux kernel's qfq_change_class() function. The vulnerability occurs due to improper handling of error cases, potentially leading to memory corruption and system instability if exploited.
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_qfq: do not free existing class in qfq_change_class()
Fixes qfq_change_class() error case.
cl->qdisc and cl should only be freed if a new class and qdisc were allocated, or we risk various UAF.