cvedb.io
CVE-2026-22976
MEDIUM · CVSS 5.5
EPSS exploitation probability: 0%
Published 2026-01-21T07:16:01.433 · Last modified 2026-06-17T10:20:37.777

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset `qfq_class->leaf_qdisc->q.qlen > 0` does not imply that the class itself is active. Two qfq_class objects may point to the same leaf_qdisc. This happens when: 1. one QFQ qdisc is attached to the dev as the root qdisc, and 2. another QFQ qdisc is temporarily referenced (e.g., via qdisc_get() / qdisc_put()) and is pending to be destroyed, as in function tc_new_tfilter. When packets are enqueued through the root QFQ qdisc, the shared leaf_qdisc->q.qlen increases. At the same time, the second QFQ qdisc triggers qdisc_put and qdisc_destroy: the qdisc enters qfq_reset() with its own q->q.qlen == 0, but its class's leaf qdisc->q.qlen > 0. T

Affected products

linux — linux_kernel

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.