CVE-2026-98012: Linux kernel · net/sched: sfq: clamp quantum in change path
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- 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.
Exploitation evidence
Disclosed: evidence found.
CVE published 25 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 has been implemented that clamps the quantum value in sfq_change() to reject values greater than 1<<20, preventing the excessive spinning condition. Users should apply the official kernel updates that include this fix. Since this is a kernel vulnerability, upgrading to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's net/sched subsystem (sfq qdisc) allows a crafted quantum value to cause a denial of service by triggering a soft lockup. The issue arises because the sfq_change() function accepts any non-negative quantum, enabling a crafted packet length to cause the deficit-refill loop to spin excessively under the qdisc lock. This requires CAP_NET_ADMIN privileges and specific configuration to exploit.
References
- ubuntu.com/security/CVE-2026-98012 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98012 (opens in a new tab)
- git.kernel.org/stable/c/f3820dce042a673fcb28cc31c87ee14257e21a17 (opens in a new tab)
- git.kernel.org/stable/c/fb9f88a33c516ea5c0bcd9a22ca288b246b34567 (opens in a new tab)
- git.kernel.org/stable/c/534cd7ecbbc6e8a974f4003a5c1557439c6e0a72 (opens in a new tab)
- git.kernel.org/stable/c/e6c1cb728e389354203a72bc77464c222a247aeb (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-98012 (opens in a new tab)
- git.kernel.org/stable/c/0692ce5a528df450d64e9f819054177e9d91076f (opens in a new tab)
- git.kernel.org/stable/c/4117c528b2de5fdc3e4a7e3626815b616a635cdc (opens in a new tab)
- git.kernel.org/stable/c/e4192bcf83aaab02129644ddf4656fd86e93751f (opens in a new tab)
- git.kernel.org/stable/c/f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0 (opens in a new tab)