CVE-2026-63844

Local GPU compromise via unsupported user fences

Published Jul 19, 2026 · Updated Jul 19, 2026

Improper user-fence handling in Linux Kernel allows local users to compromise GPU confidentiality, integrity, and availability. The JPEG v4.0.3 ring descriptor in drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c leaves no_user_fence unset, so command submission accepts unsupported 64-bit user-fence writes instead of rejecting them. Reachability requires low-privilege local access to a system exposing the affected AMDGPU JPEG ring; the public record does not specify the resulting read, write, or interruption primitive.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper user-fence handling in Linux Kernel allows local users to compromise GPU confidentiality, integrity, and availability. The JPEG v4.0.3 ring descriptor in drivers/gpu/drm/amd/amdgpu/jpeg_v4_0_3.c leaves no_user_fence unset, so command submission accepts unsupported 64-bit user-fence writes instead of rejecting them. Reachability requires low-privilege local access to a system exposing the affected AMDGPU JPEG ring; the public record does not specify the resulting read, write, or interruption primitive.

The record

CVE
CVE-2026-63844
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.5
  2. Affected versionversion=e684e654eba9481a9f462a7bbf5c385b7d1c076e <249fa7549736de1c8e327d7ca6b32fa148a40bd6
  3. Affected versionversion=e684e654eba9481a9f462a7bbf5c385b7d1c076e <83e37c0987ca92f9e87789b46dd311dcf5a4a6c8
  4. Affected versionversion=e684e654eba9481a9f462a7bbf5c385b7d1c076e <8549b3933038e68dc61cb934b9a54223dd244a78
  5. Affected versionversion=e684e654eba9481a9f462a7bbf5c385b7d1c076e <b884ff67d62ef514eee9d5f605c03101c8b6bc98
  6. Affected versionversion=e684e654eba9481a9f462a7bbf5c385b7d1c076e <d6bd2a5fd611ec9c8a2411f084cff2435c709608

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.5; version=e684e654eba9481a9f462a7bbf5c385b7d1c076e <249fa7549736de1c8e327d7ca6b32fa148a40bd6; version=e684e654eba9481a9f462a7bbf5c385b7d1c076e <83e37c0987ca92f9e87789b46dd311dcf5a4a6c8; version=e684e654eba9481a9f462a7bbf5c385b7d1c076e <8549b3933038e68dc61cb934b9a54223dd244a78; version=e684e654eba9481a9f462a7bbf5c385b7d1c076e <b884ff67d62ef514eee9d5f605c03101c8b6bc98; version=e684e654eba9481a9f462a7bbf5c385b7d1c076e <d6bd2a5fd611ec9c8a2411f084cff2435c709608

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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