Kernel crash via unchecked QFQ peek result
Published Oct 29, 2025 · Updated Oct 29, 2025
NULL-pointer dereference in the Linux kernel before 6.16 allows attackers to crash the kernel through the QFQ scheduler. The agg_dequeue function in net/sched/sch_qfq.c dereferences the result of cl->qdisc->ops->peek without first checking whether it is NULL. Public records do not identify the privileges or traffic-control configuration required to reach this dequeue path; the bounded reported consequence is a kernel crash.
Summary
What happened
NULL-pointer dereference in the Linux kernel before 6.16 allows attackers to crash the kernel through the QFQ scheduler. The agg_dequeue function in net/sched/sch_qfq.c dereferences the result of cl->qdisc->ops->peek without first checking whether it is NULL. Public records do not identify the privileges or traffic-control configuration required to reach this dequeue path; the bounded reported consequence is a kernel crash.
The record
- CVE
- CVE-2025-40083
- Published
- Oct 29, 2025
- Updated
- Oct 29, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 29, 2025CVE publishedPublication date reported by the CVE source.
- Oct 29, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dd831ac8221e691e9e918585b1003c7071df0379
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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