CVE-2026-22999: Linux kernel · Use After Free
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/2a64fb9b47afffeb5dbab5fd3a518e1436dcc90e (opens in a new tab)
- git.kernel.org/stable/c/cff6cd703f41d8071995956142729e4bba160363 (opens in a new tab)
- git.kernel.org/stable/c/f06f7635499bc806cbe2bbc8805c7cef8b1edddf (opens in a new tab)
- git.kernel.org/stable/c/0a234660dc70ce45d771cbc76b20d925b73ec160 (opens in a new tab)
- git.kernel.org/stable/c/362e269bb03f7076ba9990e518aeddb898232e50 (opens in a new tab)
- git.kernel.org/stable/c/e9d8f11652fa08c647bf7bba7dd8163241a332cd (opens in a new tab)
- git.kernel.org/stable/c/3879cffd9d07aa0377c4b8835c4f64b4fb24ac78 (opens in a new tab)