---
id: CVE-2026-63856
title: 'drm/amdgpu/vcn: set no_user_fence for VCN v2.0 enc/dec rings'
summary: |-
  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 fen…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 <
    f264019be80de79f84f464846451445923bffea0
  - >-
    Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 <
    5e777bc4cbe928ac0fd95e368fee1540f2ce4db2
  - >-
    Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 <
    ac06ce5cac9e711281585d09d00c6efcd9b86396
  - >-
    Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 <
    c71aecae98e42dcf2baf462df50b3a2cf1a93fe4
  - >-
    Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 <
    8d80b293b41fcb5e9396db93e788b0f4ebcbafb7
  - Linux 5.3
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:32:25.121168Z'
published: '2026-07-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:08.298Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63856'
references:
  - url: 'https://git.kernel.org/stable/c/f264019be80de79f84f464846451445923bffea0'
  - url: 'https://git.kernel.org/stable/c/5e777bc4cbe928ac0fd95e368fee1540f2ce4db2'
  - url: 'https://git.kernel.org/stable/c/ac06ce5cac9e711281585d09d00c6efcd9b86396'
  - url: 'https://git.kernel.org/stable/c/c71aecae98e42dcf2baf462df50b3a2cf1a93fe4'
  - url: 'https://git.kernel.org/stable/c/8d80b293b41fcb5e9396db93e788b0f4ebcbafb7'
tags:
  - cve.org
epss: 0.00175
epssPercentile: 0.06548
ingestedAt: '2026-10-16T17:24:46.771Z'
---

## Overview

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)

## Affected

- `Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 < f264019be80de79f84f464846451445923bffea0`
- `Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 < 5e777bc4cbe928ac0fd95e368fee1540f2ce4db2`
- `Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 < ac06ce5cac9e711281585d09d00c6efcd9b86396`
- `Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 < c71aecae98e42dcf2baf462df50b3a2cf1a93fe4`
- `Linux >= 1b61de45dfaff00b627e47349a019658e39268b9 < 8d80b293b41fcb5e9396db93e788b0f4ebcbafb7`
- `Linux 5.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.