CVE-2026-43417: Linux kernel · sched/mmcid: Handle vfork()/CLONE_VM correctly
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 High.
Data as of 12 Nov 2026, 20:03 UTC
Thin evidence
One scorer or noneCVSS: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
Weaponized: 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 12 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-gcp-6.11pkg:deb/ubuntu/linux-gcp-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-gcp-6.14pkg:deb/ubuntu/linux-gcp-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-hwe-6.11pkg:deb/ubuntu/linux-hwe-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-hwe-6.14pkg:deb/ubuntu/linux-hwe-6.14?arch=source&distro=nobleOther 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 for this vulnerability is available and has been applied in the affected Linux kernel versions. Users should upgrade to the patched kernel versions listed to resolve the issue. No additional mitigation actions are required beyond applying the official fix.
Description
CVE-2026-43417 is a vulnerability in the Linux kernel's scheduling subsystem related to incorrect handling of vfork()/CLONE_VM tasks. The flaw causes the kernel to stall due to an endless loop in mm_get_cid() when scheduling in a task. This happens because the logic that manages vfork()'ed tasks incorrectly accounts processed tasks, potentially skipping necessary fixups. The issue has been resolved by changing the task list walk logic to ensure proper fixup of the vfork()'ed task's CID.
References
- ubuntu.com/security/CVE-2026-43417 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-43417 (opens in a new tab)
- git.kernel.org/linus/28b5a1395036d6c7a6c8034d85ad3d7d365f192c (opens in a new tab)
- git.kernel.org/stable/c/28b5a1395036d6c7a6c8034d85ad3d7d365f192c (opens in a new tab)
- git.kernel.org/stable/c/e6761cdce78a8919a537989afb6aaf6881469f83 (opens in a new tab)