CVE-2026-98440: Linux kernel · KVM: arm64: nv: Delay freeing of shadow S2 structures until VM destruction
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.0 High.
Data as of 27 Oct 2026, 09:02 UTC
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Oct 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 delays the freeing of shadow S2 structures until VM destruction. Users should apply the updated Linux kernel versions that include this patch. The affected versions are explicitly listed and should be upgraded or patched accordingly to mitigate this vulnerability.
Description
A vulnerability in the Linux kernel's KVM module for arm64 architecture involves improper timing of freeing shadow Stage 2 (S2) structures. The issue arises because these structures are freed prematurely from kvm_arch_flush_shadow_all(), which can lead to use-after-free conditions. The fix delays freeing these shadow S2 structures until the virtual machine (VM) is fully destroyed, ensuring safe cleanup after all virtual CPUs have been terminated.
References
- ubuntu.com/security/CVE-2026-98440 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98440 (opens in a new tab)
- git.kernel.org/stable/c/22e82acec93a681071ed36f70eabe2d0c4e0bebd (opens in a new tab)
- git.kernel.org/stable/c/5bf1c9175e657b3c2dc1cf77403031ac7aadcf66 (opens in a new tab)
- git.kernel.org/stable/c/876049f026b4dfaca0cc78ec81be0e639ca8525d (opens in a new tab)
- git.kernel.org/stable/c/e5843f4effaa2ffac3e789ecd4456403564961d4 (opens in a new tab)