CVE-2026-89930 Linux Kernel KVM - Broken Access Control

Linux kernel KVM nVMX contains a broken access control vulnerability caused by missing local TLB flushes on failed nested VM-Enter, letting attackers cause stale TLB entries leading to potential privilege escalation, exploit requires nested virtualization environment.

CVSS base score 9.3 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.18% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Broken Access Control
Impact
Privilege Escalation
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published
16 September 2026
Updated
15 October 2026

Vendor fix

Update to the latest Linux kernel version containing the fix for TLB flush handling on failed nested VM-Enter.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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