Bug 2464406 (CVE-2026-31766)

Summary: CVE-2026-31766 kernel: drm/amdgpu: validate doorbell_offset in user queue creation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's AMD GPU (amdgpu) driver. A local user could exploit this vulnerability by providing a malformed doorbell offset during user queue creation. This lack of proper bounds checking allows the offset to exceed the allocated memory, potentially corrupting critical kernel memory. This could lead to a system crash (Denial of Service) or, in some scenarios, privilege escalation.
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Description OSIDB Bzimport 2026-05-01 15:05:01 UTC 
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)
Comment 1 Keith Grant 2026-05-01 22:51:36 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050147-CVE-2026-31766-dd6d@gregkh/T