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VulnerabilityPublished Updated

CVE-2026-23105: Linux kernel · Improper Input Validation

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in fac2c67bb2bb732eae4283e45fc338af7e08c254 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-06-16.

Patch
Available – fixed in fac2c67bb2bb732eae4283e45fc338af7e08c254, f27047abf7cac1b6f90c3ad60de21ef9f717c26d, d837fbee92453fbb829f950c8e7cf76207d73f33 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < fac2c67bb2bb732eae4283e45fc338af7e08c254
Fixed in
  • fac2c67bb2bb732eae4283e45fc338af7e08c254
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < f27047abf7cac1b6f90c3ad60de21ef9f717c26d
Fixed in
  • f27047abf7cac1b6f90c3ad60de21ef9f717c26d
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < d837fbee92453fbb829f950c8e7cf76207d73f33
Fixed in
  • d837fbee92453fbb829f950c8e7cf76207d73f33
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < b8c24cf5268fb3bfb8d16324c3dbb985f698c835
Fixed in
  • b8c24cf5268fb3bfb8d16324c3dbb985f698c835
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < abd9fc26ea577561a5ef6241a1b058755ffdad0c
Fixed in
  • abd9fc26ea577561a5ef6241a1b058755ffdad0c
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < 93b8635974fb050c43d07e35e5edfe6e685ca28a
Fixed in
  • 93b8635974fb050c43d07e35e5edfe6e685ca28a

AI-suggested

A fix is available and has been applied in specific commits to the Linux kernel source. Users and administrators should update their Linux kernel to a version that includes these fixes to mitigate this vulnerability. Since this is not a cloud service, manual patching is required. There is no indication that additional mitigation steps are necessary beyond applying the official fix.

Description

CVE-2026-23105 is a high-severity vulnerability in the Linux kernel's net/sched subsystem affecting version 3.8. It involves improper determination of class activation in the qfq scheduler, where reliance on the child qdisc's queue length could be manipulated. The issue was fixed by using the cl_is_active function to more reliably check class activity, preventing potential exploits related to child queue length manipulation.

References

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