CVE-2026-53079
Description
In the Linux kernel, the following vulnerability has been resolved:
net_sched: fix skb memory leak in deferred qdisc drops
When the network stack cleans up the deferred list via qdisc_run_end(),
it operates on the root qdisc. If the root qdisc do not implement the
TCQ_F_DEQUEUE_DROPS flag the packets queue to free are never freed and
gets stranded on the child's local to_free list.
Fix this by making qdisc_dequeue_drop() aware of the root qdisc. It
fetches the root qdisc and check for the TCQ_F_DEQUEUE_DROPS flag. If
the flag is present, the packet is appended directly to the root's
to_free list. Otherwise, drop it directly as it was done before the
optimization was implemented.
Summary dbcve.org
Memory leak in Linux kernel's network scheduler (net_sched) where packets queued for deferred dropping are never freed when the root qdisc doesn't implement the TCQ_F_DEQUEUE_DROPS flag, causing them to become stranded on the child's local to_free list.
Mitigation
Apply the kernel patch that makes qdisc_dequeue_drop() aware of the root qdisc and properly handles packets based on the TCQ_F_DEQUEUE_DROPS flag. Update Linux kernel to version containing the fix.