Bug 2502289 (CVE-2026-63856)

Summary: CVE-2026-63856 kernel: drm/amdgpu/vcn: set no_user_fence for VCN v2.0 enc/dec rings
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
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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Doc Text:
A flaw was found in the Linux kernel's AMDGPU Video Core Next (VCN) 2.0 component. This vulnerability arises because the VCN encoder and decoder rings do not properly support 64-bit user fence writes. An attacker could exploit this by submitting command sequences with 64-bit user fences, leading to the rejection of these submissions and a denial of service for affected applications.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-07-19 15:02:11 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu/vcn: set no_user_fence for VCN v2.0 enc/dec rings

VCN encoder and decoder rings do not support 64-bit user fence writes,
reject CS submissions with user fences.

(cherry picked from commit e2b5499fca55f1a32960a311bbb62e35891eaf73)