Improper locking in Linux kernel - CVE-2026-64100

Vulnerability identifier: #VU138532

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-2026-64100

CWE-ID: CWE-667

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 lock handling in msm_gem_shrinker_scan in the drm/msm GPU memory shrinker when reclaiming memory under shrinker context. A local user can trigger GPU memory reclaim activity to cause a denial of service.

The issue is triggered when fs_reclaim is already held and the shrinker attempts to acquire dma reservation locks, leading to a deadlock.

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/3392291fc509d8ad6e4ad90f15b0a193f721cbc9
• https://git.kernel.org/stable/c/928788566c79046f71a211fc32c115400be76402
• https://git.kernel.org/stable/c/942968260e61d4a5d7552b20814b6277f9c553df

• Improper locking in Linux kernel drm msm 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