SB20260917189 - Incorrect Conversion between Numeric Types in Linux kernel arm64 kvm

Description

This security bulletin contains information about 1 vulnerability.

1) Incorrect Conversion between Numeric Types (CVE-ID: CVE-2026-89775)

CWE-ID: CWE-681 - Incorrect Conversion between Numeric Types

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to compromise confidentiality, integrity, and availability.

The vulnerability exists due to incorrect conversion of a negative mapping level to an unsigned value in the arm64 KVM nested virtualization TLB size evaluation logic when evaluating VNCR TLB invalidation with the S1 MMU disabled. A remote attacker can trigger TLB invalidation evaluation using an S1 MMU-disabled mapping level to compromise confidentiality, integrity, and availability.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/1c9fca34b9625a67a7f1a03c8604f3df760c6c49
• https://git.kernel.org/stable/c/8053393680d4fa3eb962667d2be95dd39f0940e5
• https://git.kernel.org/stable/c/be54a70067c7dbe1381157e8a238fa4b16ea9c05