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

drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)
Published: 2026-07-19
Score: 7.8 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability resides in the Linux kernel AMDGPU VCN driver not support these writes, any command submission that includes a user fence is rejected. This flaw stops GPU command streams from executing, which can make applications that rely on VCN encoding or decoding inoperable, effectively causing a denial of service for those processes. The weakness is a fault in the driver’s handling of user‑provided data, identified as CWE‑1287.

Affected Systems

Affected systems are Linux kernel environments that use the AMDGPU VCN driver. All Linux distributions running kernel versions that have not incorporated the fix from commit ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa are vulnerable. The product is the Linux kernel; no specific distribution or kernel version list is provided beyond the presence of the VCN encoder ring.

Risk and Exploitability

The CVSS score of 7.8 indicates high severity. The EPSS score of less than 1% indicates that exploitation is unlikely and it is not listed in CISA’s KEV catalog. A command stream that includes a user fence to the AMDGPU driver would trigger the flaw, but without such capability an attacker cannot exploit the flaw. If an attacker succeeds, the impact is denial of service for GPU‑accelerated workloads on the affected machine. Because no public exploit is known but the fix is recommended.

Generated by OpenCVE AI on July 30, 2026 at 21:58 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Update the Linux kernel to a version that includes the patch rejecting 64‑bit user fence writes.
  • If an immediate kernel upgrade is not possible, configure the kernel to disable VCN or restrict GPU usage for untrusted applications.
  • Verify that applications using the VCN encoder ring do not rely on 64‑bit user fences; adjust drivers or application code accordingly.

Generated by OpenCVE AI on July 30, 2026 at 21:58 UTC.

Tracking

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Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8574-1 Linux kernel (GCP FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8593-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8574-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8595-1 Linux kernel (Oracle) vulnerabilities
Ubuntu USN Ubuntu USN USN-8596-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8595-2 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8603-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8606-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8607-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8608-1 Linux kernel (Azure FIPS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8609-1 Linux kernel (Azure CVM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8574-3 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8595-3 Linux kernel (AWS) vulnerabilities
Ubuntu USN Ubuntu USN USN-8618-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8619-1 Linux kernel (HWE) vulnerabilities
History

Tue, 21 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-1287
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 20 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}


Sun, 19 Jul 2026 14:45:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 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 ff1a5a125c5a70c328806b9bc01d7d942cf3f9aa)
Title drm/amdgpu/vcn: set no_user_fence for VCN v4.0.3 enc ring
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-05T12:36:30.612Z

Reserved: 2026-07-19T07:54:57.016Z

Link: CVE-2026-63852

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-19T00:00:00Z

Links: CVE-2026-63852 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-07-30T22:00:06Z

Weaknesses
  • CWE-1287

    Improper Validation of Specified Type of Input