Bug 2516979 (CVE-2026-74447)

Summary: CVE-2026-74447 kernel: drm/amdkfd: fix uint32_t overflow in EOP ring buffer size alignment
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `drm/amdkfd` component. An integer overflow vulnerability exists when aligning the End-of-Pipe (EOP) ring buffer size. A local attacker could exploit this by providing a specially crafted size that, due to a 32-bit integer overflow, causes the system to bypass buffer size checks. This could lead to writes beyond the intended buffer, potentially causing a Graphics Processing Unit (GPU) fault and resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-08-15 12:42:22 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/amdkfd: fix uint32_t overflow in EOP ring buffer size alignment

eop_ring_buffer_size in struct queue_properties is a u32. In
kfd_queue_acquire_buffers() the expected EOP buffer size is computed as
ALIGN(eop_ring_buffer_size, PAGE_SIZE); ALIGN uses typeof(x), so the
addition is done in 32-bit. A user-supplied size of 0xFFFFF001 wraps to
0, causing kfd_queue_buffer_get() to skip its exact-size check (gated on
size != 0) and accept any BO mapped at the address. On GFX8/GFX9 the MQD
cp_hqd_eop_control is then programmed for an 8KB EOP ring backed by a 4KB
BO, so CP EOP writes can land past the buffer and fault the GPU.

Cast the operand to u64 so the alignment is computed in 64-bit; the size
check in kfd_queue_buffer_get() then rejects the oversized request.

(cherry picked from commit ae443117b742c357bfef3a7bddabf76fcf86e9ef)
Comment 1 gkamathe 2026-08-21 08:23:43 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081530-CVE-2026-74447-c47e@gregkh/T