---
id: CVE-2026-63855
title: 'drm/amdgpu/vcn: set no_user_fence for VCN v2.5 enc/dec rings'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  drm/amdgpu/vcn: set no_user_fence for VCN v2.5 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 >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d <
    2c6fb056567efb49f8674108b86088a1cfaa86d0
  - >-
    Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d <
    8f0ea4524dc71c6c9ec97f2711f46e12f624140f
  - >-
    Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d <
    602d4c5872b25ddd4d82fb2025efb9a05b187bb3
  - >-
    Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d <
    5a3c6f76cab164a5d803084908d7050f649ab7f9
  - >-
    Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d <
    4f317863a3ab212a027d8c8c3cc3af4e3fb95704
  - Linux 5.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:32:22.667512Z'
published: '2026-07-19'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:42:08.154Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63855'
references:
  - url: 'https://git.kernel.org/stable/c/2c6fb056567efb49f8674108b86088a1cfaa86d0'
  - url: 'https://git.kernel.org/stable/c/8f0ea4524dc71c6c9ec97f2711f46e12f624140f'
  - url: 'https://git.kernel.org/stable/c/602d4c5872b25ddd4d82fb2025efb9a05b187bb3'
  - url: 'https://git.kernel.org/stable/c/5a3c6f76cab164a5d803084908d7050f649ab7f9'
  - url: 'https://git.kernel.org/stable/c/4f317863a3ab212a027d8c8c3cc3af4e3fb95704'
tags:
  - cve.org
epss: 0.00175
epssPercentile: 0.06554
ingestedAt: '2026-10-16T17:24:46.769Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu/vcn: set no_user_fence for VCN v2.5 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 efc9dd5590894109bce9a0bfe1fa5592dd6b20b1)

## Affected

- `Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 2c6fb056567efb49f8674108b86088a1cfaa86d0`
- `Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 8f0ea4524dc71c6c9ec97f2711f46e12f624140f`
- `Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 602d4c5872b25ddd4d82fb2025efb9a05b187bb3`
- `Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 5a3c6f76cab164a5d803084908d7050f649ab7f9`
- `Linux >= 28c17d72072b7ce5cc13a527dcbfc045cc995e7d < 4f317863a3ab212a027d8c8c3cc3af4e3fb95704`
- `Linux 5.4`

## Remediation

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