CVE-2026-22976

Local kernel crash via inactive QFQ deactivation

Published Jan 21, 2026 · Updated Jan 21, 2026

NULL pointer dereference in the Linux Kernel QFQ scheduler allows local users to crash the kernel through crafted traffic-control operations. qfq_reset treats a shared leaf qdisc's nonzero queue length as proof that its own class is active, then qfq_deactivate_agg dereferences an inactive aggregate. Reaching the fault requires local low-privilege access and a QFQ configuration in which a root qdisc shares a leaf with another qdisc being destroyed.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux Kernel QFQ scheduler allows local users to crash the kernel through crafted traffic-control operations. qfq_reset treats a shared leaf qdisc's nonzero queue length as proof that its own class is active, then qfq_deactivate_agg dereferences an inactive aggregate. Reaching the fault requires local low-privilege access and a QFQ configuration in which a root qdisc shares a leaf with another qdisc being destroyed.

The record

CVE
CVE-2026-22976
Published
Jan 21, 2026
Updated
Jan 21, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 21, 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.

  1. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <0809c4bc06c9c961222df29f2eccfd449304056f
  2. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <11bf9134613f6c71fc0ff36c5d8d33856f6ae3bb
  3. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <43497313d0da3e12b5cfcd97aa17bf48ee663f95
  4. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <51ffd447bc37bf1a5776b85523f51d2bc69977f6
  5. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <6116a83ec167d3ab1390cded854d237481f41b63
  6. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <c1d73b1480235731e35c81df70b08f4714a7d095
  7. Affected versionversion=0545a3037773512d3448557ba048cebb73b3e4af <cdb24200b043438a144df501f1ebbd926bb1a2c7
  8. Affected versionversion=3.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0545a3037773512d3448557ba048cebb73b3e4af <0809c4bc06c9c961222df29f2eccfd449304056f; version=0545a3037773512d3448557ba048cebb73b3e4af <11bf9134613f6c71fc0ff36c5d8d33856f6ae3bb; version=0545a3037773512d3448557ba048cebb73b3e4af <43497313d0da3e12b5cfcd97aa17bf48ee663f95; version=0545a3037773512d3448557ba048cebb73b3e4af <51ffd447bc37bf1a5776b85523f51d2bc69977f6; version=0545a3037773512d3448557ba048cebb73b3e4af <6116a83ec167d3ab1390cded854d237481f41b63; version=0545a3037773512d3448557ba048cebb73b3e4af <c1d73b1480235731e35c81df70b08f4714a7d095; version=0545a3037773512d3448557ba048cebb73b3e4af <cdb24200b043438a144df501f1ebbd926bb1a2c7; version=3.0

Published CVSS scores

5.5NISTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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