Kernel code execution via ETS scheduler race
Published Jan 13, 2026 · Updated Jan 13, 2026
Use-after-free in the ETS scheduler in Linux Kernel allows local users to execute arbitrary code in the kernel context. ets_qdisc_change unlocks the scheduler before releasing removed classes' Qdisc references, leaving active-list entries that ets_qdisc_dequeue can dereference after free. Triggering the race requires capabilities to create user and network namespaces and to reconfigure an ETS qdisc while dequeue activity occurs.
Summary
What happened
Use-after-free in the ETS scheduler in Linux Kernel allows local users to execute arbitrary code in the kernel context. ets_qdisc_change unlocks the scheduler before releasing removed classes' Qdisc references, leaving active-list entries that ets_qdisc_dequeue can dereference after free. Triggering the race requires capabilities to create user and network namespaces and to reconfigure an ETS qdisc while dequeue activity occurs.
The record
- CVE
- CVE-2025-71066
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-362, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 13, 2026CVE publishedPublication date reported by the CVE source.
- Jan 13, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.16
- Affected versionversion=ae2659d2c670252759ee9c823c4e039c0e05a6f2
- Affected versionversion=de6d25924c2a8c2988c6a385990cafbe742061bf <06bfb66a7c8b45e3fed01351a4b087410ae5ef39
- Affected versionversion=de6d25924c2a8c2988c6a385990cafbe742061bf <45466141da3c98a0c5fa88be0bc14b4b6a4bd75c
- Affected versionversion=de6d25924c2a8c2988c6a385990cafbe742061bf <9987cda315c08f63a02423fa2f9a1f6602c861a0
- Affected versionversion=de6d25924c2a8c2988c6a385990cafbe742061bf <a75d617a4ef08682f5cfaadc01d5141c87e019c9
- Affected versionversion=de6d25924c2a8c2988c6a385990cafbe742061bf <ce052b9402e461a9aded599f5b47e76bc727f7de
- Affected versionversion=e25bdbc7e951ae5728fee1f4c09485df113d013c
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- ETS qdisc race reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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