CVE-2026-89915 Linux Kernel KVM arm64 - Authentication Bypass

Linux kernel KVM arm64 contains a broken authentication caused by flawed VM-wide VNCR mapping counter logic, letting attackers potentially bypass TLB invalidation guarantees, exploit requires specific CPU and VM conditions.

CVSS base score 9.3 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.19% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Authentication Bypass
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.

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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