CVE-2026-98009: Linux kernel · net/sched: ets: clamp quantum in parse and fallback paths
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 12:55 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 values in both fallback and explicit configuration paths to prevent the deficit-refill loop from spinning. Users should apply the updated Linux kernel versions that include this fix. Since this is a kernel-level vulnerability requiring CAP_NET_ADMIN privileges, ensuring systems are updated to patched kernel versions is the primary mitigation.
Description
A vulnerability in the Linux kernel's net/sched ETS (Earliest TxTime Scheduler) component was resolved. The issue involves the ets_qdisc_change() function falling back to psched_mtu() without a proper floor for bands lacking an explicit quantum, which can cause a deficit-refill loop to spin under the qdisc lock. This occurs when a crafted size table causes qdisc_pkt_len to reach approximately 2 GiB, combined with a zero psched_mtu on a headerless device. The fix clamps explicitly configured quanta to a range between 256 and 1<<20 to prevent this condition.
References
- ubuntu.com/security/CVE-2026-98009 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98009 (opens in a new tab)
- git.kernel.org/stable/c/1c38487f46b243bfeefec0c0c86023a3904f2214 (opens in a new tab)
- git.kernel.org/stable/c/8f80b113dea0bed3c1a31a4224b72775cd9ec52d (opens in a new tab)
- git.kernel.org/stable/c/de22c30ec5598aca8797f02082d2ee1358dfa3ff (opens in a new tab)
- git.kernel.org/stable/c/99ae477b892e203a37985ebc56f0063e072f7f4b (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-98009 (opens in a new tab)
- git.kernel.org/stable/c/226d2702e74a570f5bfae6115b4706da4b94e5cf (opens in a new tab)
- git.kernel.org/stable/c/440b66cc7b56ea38e9b878ae88da91992efaa4c4 (opens in a new tab)
- git.kernel.org/stable/c/4ef8664eafafc8db68a1d52601f17dc008a223b7 (opens in a new tab)
- git.kernel.org/stable/c/8b8d782c3b96376217087767dcf662cd3d25f226 (opens in a new tab)