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

drm/amdgpu/vcn: set no_user_fence for VCN v3.0 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 663bed3c7b8b9a7624b0d95d300ddae034ad0614)
Published: 2026-07-19
Score: 7.8 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The Linux kernel’s DRM/amdgpu driver contains a flaw in the VCN v3.0 encoder and decoder rings. The driver does not correctly process 64‑bit user fence writes, causing it to reject command‑submission packets that include such fences. As a result, any GPU workload that relies on 64‑bit user fences cannot be executed, effectively denying the affected GPU services. The vulnerability is identified as CWE‑1287, an access‑control exception that leads to a service‑availability impact rather than privilege escalation or data disclosure.

Affected Systems

All Linux kernel installations that include the unpatched amdgpu driver with VCN v3.0 rings are vulnerable. No specific kernel version is listed in the CVE description; therefore any kernel lacking commit 663bed3c7b8b9a7624b0d95d300ddae034ad0614 is at risk. Distributions should verify that their kernel or driver package contains this commit before allowing user workloads that depend on the affected rings.

Risk and Exploitability

The CVSS score of 7.8 indicates a high severity denial‑of‑service condition. The EPSS value of < 1 % signals a very low probability of exploitation in the wild. The vulnerability is not listed in CISA’s KEV catalog. The likely attack vector is local or privileged code that can submit command‑submission packets containing 64‑bit user fences to the VCN rings; a remote attacker would need such local or privileged access to exploit this weakness. Consequently, the overall exploitation risk is low for remote attackers but would be higher for systems where local code can manipulate GPU submissions.

Generated by OpenCVE AI on August 1, 2026 at 07:57 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Update the Linux kernel or the amdgpu driver to a release that incorporates commit 663bed3c7b8b9a7624b0d95d300ddae034ad0614 and reboot to load the updated components.
  • If an immediate kernel upgrade is not possible, mitigate by disabling the amdgpu module or the VCN rings, for example with the kernel parameter kmod.blacklist=amdgpu or by unloading the module.
  • As a temporary measure, limit GPU workloads to avoid using 64‑bit user fences, or modify applications to rely on supported fence sizes until the patch is applied.

Generated by OpenCVE AI on August 1, 2026 at 07:57 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


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 v3.0 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 663bed3c7b8b9a7624b0d95d300ddae034ad0614)
Title drm/amdgpu/vcn: set no_user_fence for VCN v3.0 enc/dec rings
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: 2026-08-05T12:36:32.766Z

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

Link: CVE-2026-63854

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity :

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

Links: CVE-2026-63854 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-01T08:00:14Z

Weaknesses
  • CWE-1287

    Improper Validation of Specified Type of Input