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VulnerabilityPublished Updated

CVE-2026-22999: Linux kernel · Use After Free

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f06f7635499bc806cbe2bbc8805c7cef8b1edddf : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 14% 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 f06f7635499bc806cbe2bbc8805c7cef8b1edddf, e9d8f11652fa08c647bf7bba7dd8163241a332cd, cff6cd703f41d8071995956142729e4bba160363 +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 25 Jan 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, < f06f7635499bc806cbe2bbc8805c7cef8b1edddf
Fixed in
  • f06f7635499bc806cbe2bbc8805c7cef8b1edddf
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < e9d8f11652fa08c647bf7bba7dd8163241a332cd
Fixed in
  • e9d8f11652fa08c647bf7bba7dd8163241a332cd
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < cff6cd703f41d8071995956142729e4bba160363
Fixed in
  • cff6cd703f41d8071995956142729e4bba160363
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < 3879cffd9d07aa0377c4b8835c4f64b4fb24ac78
Fixed in
  • 3879cffd9d07aa0377c4b8835c4f64b4fb24ac78
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < 362e269bb03f7076ba9990e518aeddb898232e50
Fixed in
  • 362e269bb03f7076ba9990e518aeddb898232e50
LinuxLinuxAffected
  • ≥ 462dbc9101acd38e92eda93c0726857517a24bbd, < 2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e
Fixed in
  • 2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e

AI-suggested

A fix is available and has been applied in multiple Linux kernel commits. Users and administrators should update their Linux kernel to a version that includes these fixes. Since this is not a cloud service, manual patching is required. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-22999 is a high-severity use-after-free vulnerability in the Linux kernel's net/sched subsystem, specifically in the sch_qfq module. The flaw occurs in the qfq_change_class() function where existing classes may be freed incorrectly, leading to potential memory corruption. This issue has been fixed by ensuring that class and qdisc objects are only freed if newly allocated, preventing use-after-free conditions.

References

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