Use of Uninitialized Variable in Linux kernel - CVE-2026-46182

Vulnerability identifier: #VU133018

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-46182

CWE-ID: CWE-457

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to disclose sensitive information.

The vulnerability exists due to uninitialized stack memory in papr_hvpipe when copying a header structure to userspace. A local user can trigger the affected operation to disclose sensitive information.

The issue is caused by uninitialized padding bytes in the structure being exposed through copy_to_user().

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oem-7.0 (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 (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-oem-7.0 (Ubuntu package) - update to 7.0.0-1009.9
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/0479b6e9f999cc1cbad7d9f09f574fc387e605d5
• https://git.kernel.org/stable/c/cefeed44296261173a806bef988b26bc565da4be
• https://git.kernel.org/stable/c/f88f8e4485b437e0a2f96a7ff1f88aa22d925659

• Use of Uninitialized Variable in Linux kernel platforms pseries
• 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