Improper input validation in Linux kernel - CVE-2026-46156

Vulnerability identifier: #VU133032

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-46156

CWE-ID: CWE-20

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper input validation in loongson_gpu_fixup_dma_hang() when scanning PCI devices during system initialization. A local user can attach a discrete GPU in a configuration that causes an invalid register address to be used to trigger a kernel panic.

The issue occurs on LoongArch systems when a discrete GPU is present and the switch logic does not match the expected device cases.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-ibm (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

linux (Ubuntu package) - addressed in versions 7.0.0-28.28, 7.0.0-28.28.1, 7.0.0-1003.4, 7.0.0-1008.8
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1009.9
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/07d190e4ec689d6478f7f5e36099fb9bf457e7c5
• https://git.kernel.org/stable/c/2cb19b06c09983727573bbe7d7430cbad480a714
• https://git.kernel.org/stable/c/81fef1c278436e6bd68ee4ca05a0acb96e256561
• https://git.kernel.org/stable/c/8dfa2f8780e486d05b9a0ffce70b8f5fbd62053e
• https://git.kernel.org/stable/c/9e1aed63a5552958ef2a9bfd699a3f990e52a77f

• Improper input validation in Linux kernel loongarch pci
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure-7.0