Kernel compromise via QFQ class-change use-after-free
Published Jan 25, 2026 · Updated Jan 25, 2026
Use-after-free in the Linux Kernel QFQ scheduler allows local users to compromise the running kernel through traffic-control messages. The qfq_change_class() error path frees an existing class and its qdisc even though that invocation allocated neither object, leaving live references to freed memory. Reachability requires local rtnetlink access to submit QFQ class-change requests; reuse of the freed objects can expose or alter kernel memory or crash the system.
Summary
What happened
Use-after-free in the Linux Kernel QFQ scheduler allows local users to compromise the running kernel through traffic-control messages. The qfq_change_class() error path frees an existing class and its qdisc even though that invocation allocated neither object, leaving live references to freed memory. Reachability requires local rtnetlink access to submit QFQ class-change requests; reuse of the freed objects can expose or alter kernel memory or crash the system.
The record
- CVE
- CVE-2026-22999
- Published
- Jan 25, 2026
- Updated
- Jan 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 25, 2026CVE publishedPublication date reported by the CVE source.
- Jan 25, 2026Record 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=3.8
- Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <362e269bb03f7076ba9990e518aeddb898232e50
- Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <3879cffd9d07aa0377c4b8835c4f64b4fb24ac78
- Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <e9d8f11652fa08c647bf7bba7dd8163241a332cd
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
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Technologies
Your stack
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Your stack
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