CVE-2026-22976: Linux kernel · net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 High · fixed in 5.15.0-1103.110~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1103.110~20.04.1, 5.15.0-1110.119~20.04.1, 5.15.0-1103.112~20.04.1 +68
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 21 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 |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and has been released in updated Linux kernel packages. Users should apply the official kernel updates provided by their distribution, such as the Ubuntu security notices USN-8096-1 and USN-8096-2, and reboot the system to apply changes. Due to ABI changes, recompilation and reinstallation of third-party kernel modules may be necessary. No additional mitigations are required beyond applying the official patches.
Description
A vulnerability in the Linux kernel's net/sched subsystem (sch_qfq) could cause a NULL pointer dereference when deactivating an inactive aggregate. This occurs due to improper handling of shared leaf_qdisc objects between multiple qfq_class instances, leading to a kernel crash. The issue has been resolved in updated Linux kernel versions.
References
- ubuntu.com/security/CVE-2026-22976 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-22976 (opens in a new tab)
- git.kernel.org/linus/c1d73b1480235731e35c81df70b08f4714a7d095 (opens in a new tab)
- git.kernel.org/stable/c/0809c4bc06c9c961222df29f2eccfd449304056f (opens in a new tab)
- git.kernel.org/stable/c/11bf9134613f6c71fc0ff36c5d8d33856f6ae3bb (opens in a new tab)
- git.kernel.org/stable/c/43497313d0da3e12b5cfcd97aa17bf48ee663f95 (opens in a new tab)
- git.kernel.org/stable/c/51ffd447bc37bf1a5776b85523f51d2bc69977f6 (opens in a new tab)
- git.kernel.org/stable/c/6116a83ec167d3ab1390cded854d237481f41b63 (opens in a new tab)
- git.kernel.org/stable/c/c1d73b1480235731e35c81df70b08f4714a7d095 (opens in a new tab)
- git.kernel.org/stable/c/cdb24200b043438a144df501f1ebbd926bb1a2c7 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8116-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8096-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8141-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8163-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8243-1 (opens in a new tab)