Improper initialization in Linux kernel - CVE-2026-89908

Vulnerability identifier: #VU150384

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-2026-89908

CWE-ID: CWE-665

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to compromise confidentiality, integrity, and availability.

The vulnerability exists due to improper preservation of memslot architecture flags in the LoongArch KVM memory-region handling code when processing a KVM_MR_FLAGS_ONLY memory-region update. A local user can perform a KVM_MR_FLAGS_ONLY update to compromise confidentiality, integrity, and availability.

The issue occurs when guest physical and host virtual address offsets within a PMD differ.

Linux kernel
Debian Linux
Ubuntu
linux-nvidia-tegra (Ubuntu package)
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)
linux (Debian package)

Install security update from vendor's repository.

linux-nvidia-tegra (Ubuntu package) - update to 6.8.0-1038.42
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
linux (Debian package) - update to 6.12.111-1

• https://git.kernel.org/stable/c/27a9bfee3bbcb3cabb77797354f07e0e44e49831
• https://git.kernel.org/stable/c/4e4dbc341b1581dc512b85d98b768373b0398366
• https://git.kernel.org/stable/c/7c6df65b53846cd7a9a1c81c6ddb42fdc08603e8
• https://git.kernel.org/stable/c/bc7a6849b4395f45a602db91b0fb2fb2e9ed4bba

• Improper initialization in Linux kernel loongarch kvm
• Debian update for linux
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more
• Ubuntu update for linux-nvidia-tegra