CVE-2026-98017: Linux kernel · net/sched: defer qdisc freeing after failed creation
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 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 is available that defers the freeing of failed qdiscs to an RCU callback, preventing synchronous freeing while references may still exist. Users should apply the official Linux kernel updates that include this fix. Since this is not a cloud service, remediation depends on patching affected systems.
Description
A vulnerability in the Linux kernel's network scheduler (net/sched) related to the handling of RTM_NEWQDISC requests has been resolved. The flaw involves improper freeing of queueing disciplines (qdiscs) after failed creation when an invalid TCA_RATE causes estimator setup to fail. This can lead to a use-after-free condition where a qdisc is freed while still potentially in use by tc_run().
References
- ubuntu.com/security/CVE-2026-98017 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98017 (opens in a new tab)
- git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e (opens in a new tab)
- git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea (opens in a new tab)
- git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101 (opens in a new tab)
- git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-98017 (opens in a new tab)
- git.kernel.org/stable/c/6a1b49bb9fdf9e8e7aa38e8cd635c0cc4074447d (opens in a new tab)
- git.kernel.org/stable/c/96a27a3e64e7c87abade03fb2ad04ed66992a89a (opens in a new tab)