CVE-2026-43326: Linux kernel · sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium : upgrade to 7.0.0-1006.6 when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.08% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.0.0-1006.6
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 8 May 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 the Ubuntu linux-nvidia package to 7.0.0-1006.6.
Affected software
| Product | 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-nvidiapkg:deb/ubuntu/linux-nvidia?arch=source&distro=resoluteOther threats | 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– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available that fixes this deadlock by changing the waiting mechanism to use a balance callback with rescheduling instead of busy-waiting. Users should apply the official kernel updates that include this fix. Since this is a kernel-level issue, updating to a fixed kernel version is the recommended remediation.
Description
A deadlock vulnerability in the Linux kernel's sched_ext subsystem (CVE-2026-43326) has been fixed. The issue involved a busy-wait loop in kick_cpus_irq_workfn() that could cause multiple CPUs to deadlock by forming a wait cycle. The fix replaces the busy-wait with a reschedule mechanism that defers waiting to a balance callback, allowing CPUs to advance their synchronization state and avoid deadlocks. This vulnerability affects specific versions of the linux-hwe-edge kernel and has a medium severity rating with no confidentiality or integrity impact but a high availability impact.
References
- ubuntu.com/security/CVE-2026-43326 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43326 (opens in a new tab)
- git.kernel.org/linus/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c (opens in a new tab)
- git.kernel.org/stable/c/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c (opens in a new tab)
- git.kernel.org/stable/c/c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54 (opens in a new tab)