CVE-2026-23105

Local kernel compromise via QFQ state desynchronization

Published Feb 4, 2026 · Updated Feb 4, 2026

Use-after-free in the Linux Kernel QFQ scheduler allows local users with CAP_NET_ADMIN to corrupt kernel memory or crash the host. qfq_rm_from_ag treats child qdisc qlen as the class activation state; manipulated queue lengths can skip deactivation, leave the class linked to a freed aggregate, and later dereference freed memory. CAP_NET_ADMIN in a user and network namespace is sufficient; a separate double-deactivation path causes a NULL-pointer kernel panic.

CVSS severity7.8
High
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

Use-after-free in the Linux Kernel QFQ scheduler allows local users with CAP_NET_ADMIN to corrupt kernel memory or crash the host. qfq_rm_from_ag treats child qdisc qlen as the class activation state; manipulated queue lengths can skip deactivation, leave the class linked to a freed aggregate, and later dereference freed memory. CAP_NET_ADMIN in a user and network namespace is sufficient; a separate double-deactivation path causes a NULL-pointer kernel panic.

The record

CVE
CVE-2026-23105
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 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=3.8
  2. Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <77f1afd0bb4d5da95236f6114e6d0dfcde187ff6
  3. Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <93b8635974fb050c43d07e35e5edfe6e685ca28a
  4. Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <abd9fc26ea577561a5ef6241a1b058755ffdad0c
  5. Affected versionversion=462dbc9101acd38e92eda93c0726857517a24bbd <d837fbee92453fbb829f950c8e7cf76207d73f33

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.8; version=462dbc9101acd38e92eda93c0726857517a24bbd <77f1afd0bb4d5da95236f6114e6d0dfcde187ff6; version=462dbc9101acd38e92eda93c0726857517a24bbd <93b8635974fb050c43d07e35e5edfe6e685ca28a; version=462dbc9101acd38e92eda93c0726857517a24bbd <abd9fc26ea577561a5ef6241a1b058755ffdad0c; version=462dbc9101acd38e92eda93c0726857517a24bbd <d837fbee92453fbb829f950c8e7cf76207d73f33

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7Oracle LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

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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

T1068Exploitation for Privilege Escalation

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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