Improper input validation in Linux kernel - CVE-2026-63878

Vulnerability identifier: #VU138778

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-2026-63878

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 GEM_OP GET_MAPPING_INFO handling in amdgpu_gem.c when processing a user-supplied num_entries value. A local user can supply an oversized num_entries value to cause a denial of service.

On systems configured with CONFIG_PANIC_ON_WARN=y, the issue can lead to a kernel panic.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
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/967a00b8e06a7734aded23861faba9ee2462be87
• https://git.kernel.org/stable/c/a1ba4594232c87c3b8defd6f89a2e40f8b08395d
• https://git.kernel.org/stable/c/f059b4c493df3e54fe3ffe4658009c31864275da

• Improper input validation in Linux kernel amd amdgpu driver
• 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