In the Linux kernel, the following vulnerability has been resolved:

sch/netem: fix use after free in netem_dequeue

If netem_dequeue() enqueues packet to inner qdisc and that qdisc
returns __NET_XMIT_STOLEN. The packet is dropped but
qdisc_tree_reduce_backlog() is not called to update the parent's
q.qlen, leading to the similar use-after-free as Commit
e04991a48dbaf382 ("netem: fix return value if duplicate enqueue
fails")

Commands to trigger KASAN UaF:

ip link add type dummy
ip link set lo up
ip link set dummy0 up
tc qdisc add dev lo parent root handle 1: drr
tc filter add dev lo parent 1: basic classid 1:1
tc class add dev lo classid 1:1 drr
tc qdisc add dev lo parent 1:1 handle 2: netem
tc qdisc add dev lo parent 2: handle 3: drr
tc filter add dev lo parent 3: basic classid 3:1 action mirred egress
redirect dev dummy0
tc class add dev lo classid 3:1 drr
ping -c1 -W0.01 localhost # Trigger bug
tc class del dev lo classid 1:1
tc class add dev lo classid 1:1 drr
ping -c1 -W0.01 localhost # UaF

kernel.org https://git.kernel.org/stable/c/14f91ab8d391f249b845916820a56f42cf747241 [No types assigned]

kernel.org https://git.kernel.org/stable/c/295ad5afd9efc5f67b86c64fce28fb94e26dc4c9 [No types assigned]

kernel.org https://git.kernel.org/stable/c/32008ab989ddcff1a485fa2b4906234c25dc5cd6 [No types assigned]

kernel.org https://git.kernel.org/stable/c/3b3a2a9c6349e25a025d2330f479bc33a6ccb54a [No types assigned]

kernel.org https://git.kernel.org/stable/c/98c75d76187944296068d685dfd8a1e9fd8c4fdc [No types assigned]

kernel.org https://git.kernel.org/stable/c/db2c235682913a63054e741fe4e19645fdf2d68e [No types assigned]

kernel.org https://git.kernel.org/stable/c/dde33a9d0b80aae0c69594d1f462515d7ff1cb3d [No types assigned]

kernel.org https://git.kernel.org/stable/c/f0bddb4de043399f16d1969dad5ee5b984a64e7b [No types assigned]