CVE-2026-43496

/// Technical description

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

net/sched: sch_red: Replace direct dequeue call with peek and qdisc_dequeue_peeked

When red qdisc has children (eg qfq qdisc) whose peek() callback is

qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such

qdiscs (eg illustrated in patch #3 as tbf) wants to retrieve an skb from

its child (red in this case), it will do the following:

1a. do a peek() - and when sensing there's an skb the child can offer, then

- the child in this case(red) calls its child's (qfq) peek.

qfq does the right thing and will return the gso_skb queue packet.

Note: if there wasnt a gso_skb entry then qfq will store it there.

1b. invoke a dequeue() on the child (red). And herein lies the problem.

- red will call the child's dequeue() which will essentially just

try to grab something of qfq's queue.

[ 78.667668][ T363] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References