Linux Kernel up to 6.18.21/6.19.11 amdgpu amdgpu_userq_get_doorbell_index allocation of resources

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.18.21/6.19.11. The impacted element is the function amdgpu_userq_get_doorbell_index of the component amdgpu. Such manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2026-31766. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.21/6.19.11. It has been rated as critical. Affected by this issue is the function amdgpu_userq_get_doorbell_index of the component amdgpu. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: validate doorbell_offset in user queue creation amdgpu_userq_get_doorbell_index() passes the user-provided doorbell_offset to amdgpu_doorbell_index_on_bar() without bounds checking. An arbitrarily large doorbell_offset can cause the calculated doorbell index to fall outside the allocated doorbell BO, potentially corrupting kernel doorbell space. Validate that doorbell_offset falls within the doorbell BO before computing the BAR index, using u64 arithmetic to prevent overflow. (cherry picked from commit de1ef4ffd70e1d15f0bf584fd22b1f28cbd5e2ec)

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-31766 since 03/09/2026. There are known technical details, but no exploit is available.

Upgrading to version 6.18.22 or 6.19.12 eliminates this vulnerability. Applying the patch 3543005a42d7e8e12b21897ef6798541bf7cbcd3/86b732fbc37ce4fb76cdd4af0fb7e30a6acdbce6/a018d1819f158991b7308e4f74609c6c029b670c 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.

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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
• 6.18.19
• 6.18.20
• 6.18.21
• 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
• 6.19.9
• 6.19.10
• 6.19.11

License

• open-source

Website

• Vendor: https://www.kernel.org/

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