Incorrect Conversion between Numeric Types in Linux kernel - CVE-2026-89775

Vulnerability identifier: #VU150511

CSH Severity: Low

CVSS v4: 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]

CVE-ID: CVE-2026-89775

CWE-ID: CWE-681

Exploitation vector: Local access

Exploit availability: No public exploit available

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.

Linux kernel
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for x86_64
Ubuntu
linux (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-oracle (Ubuntu package)
linux-ibm (Ubuntu package)
linux-hwe-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
kernel (Red Hat package)

Install security update from vendor's repository.

linux (Ubuntu package) - update to 7.0.0-42.42
linux-aws (Ubuntu package) - update to 7.0.0-1016.17
linux-gcp (Ubuntu package) - update to 7.0.0-1016.18
linux-oracle (Ubuntu package) - update to 7.0.0-1015.16
linux-ibm (Ubuntu package) - update to 7.0.0-1017.17
linux-hwe-7.0 (Ubuntu package) - update to 7.0.0-42.42~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1017.17
kernel (Red Hat package) - update to 6.12.0-211.61.1.el10_2

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

• Incorrect Conversion between Numeric Types in Linux kernel arm64 kvm
• Red Hat Enterprise Linux 10 update for kernel
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more