CVE-2025-21978: linux kernel — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: drm/hyperv: Fix address space leak when Hyper-V DRM device is removed When a Hyper-V DRM device is probed, the driver allocates MMIO space for the vram, and maps it cacheable. If the device removed, or in the error path for device probing, the MMIO space is released but no unmap is done. Consequently the kernel address space for the mapping is leaked. Fix this by adding iounmap() calls in the device removal path, and in the error path during device probing.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-401 CWE-401

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.0 — 6.1.132
linux	linux_kernel	6.2 — 6.6.84
linux	linux_kernel	6.7 — 6.12.20
linux	linux_kernel	6.13 — 6.13.8
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/158242b56bf465a73e1edeac0fe828a8acad4499 https://git.kernel.org/stable/c/24f1bbfb2be77dad82489c1468bbb14312aab129 https://git.kernel.org/stable/c/ad27b4a51495490b815580d9b935e8eee14d1a9c https://git.kernel.org/stable/c/aed709355fd05ef747e1af24a1d5d78cd7feb81e https://git.kernel.org/stable/c/c40cd24bfb9bfbb315c118ca14ebe6cf52e2dd1e

Other References

https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html

Frequently Asked Questions

What is CVE-2025-21978? +

In the Linux kernel, the following vulnerability has been resolved: drm/hyperv: Fix address space leak when Hyper-V DRM device is removed When a Hyper-V DRM device is probed, the driver allocates MMIO space for the vram, and maps it cacheable. If the device removed, or in the error path for device probing, the MMIO space is released but no unmap is done. Consequently the kernel address space for the mapping is leaked. Fix this by adding iounmap() calls in the device removal path, and in the error path during device probing. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-21978? +

CVE-2025-21978 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-21978? +

CVE-2025-21978 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-21978? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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