Linux Kernel up to 6.18.18/6.19.8 amdgpu_userq_signal_ioctl input validation

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.18.18/6.19.8. This affects the function amdgpu_userq_signal_ioctl. The manipulation leads to input validation. This vulnerability is uniquely identified as CVE-2026-43400. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.18/6.19.8. It has been rated as critical. This issue affects the function amdgpu_userq_signal_ioctl. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: add upper bound check on user inputs in signal ioctl Huge input values in amdgpu_userq_signal_ioctl can lead to a OOM and could be exploited. So check these input value against AMDGPU_USERQ_MAX_HANDLES which is big enough value for genuine use cases and could potentially avoid OOM. (cherry picked from commit be267e15f99bc97cbe202cd556717797cdcf79a5)

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-43400 since 05/01/2026. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/22/2026).

The vulnerability scanner Nessus provides a plugin with the ID 313400 (Linux Distros Unpatched Vulnerability : CVE-2026-43400), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.19 or 6.19.9 eliminates this vulnerability. Applying the patch 6fff5204d8aa26b1be50b6427f833bd3e8899c4f/46630d966b99b0fc6cb01fef4110587f3375a0c0/ea78f8c68f4f6211c557df49174c54d167821962 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (313400). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 6.19.7
• 6.19.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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