CVE-2026-63983

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net/sched: fix packet loop on netem when duplicate is on<br /> <br /> When netem duplicates a packet it re-enqueues the copy at the root qdisc.<br /> If another netem sits in the tree the copy can be duplicated<br /> again, recursing until the stack or memory is exhausted.<br /> <br /> The original duplication guard temporarily zeroed q-&gt;duplicate around<br /> the re-enqueue, but that does not cover all cases because it is<br /> per-qdisc state shared across all concurrent enqueue paths<br /> and is not safe without additional locking.<br /> <br /> Use the skb tc_depth field introduced in an earlier patch:<br /> - increment it on the duplicate before re-enqueue<br /> - skip duplication for any skb whose tc_depth is already non-zero.<br /> <br /> This marks the packet itself rather than mutating qdisc state,<br /> therefore it is safe regardless of tree topology or concurrency.