CVE-2026-63856

GPU-buffer corruption via unsupported user fences

Published Jul 19, 2026 · Updated Jul 19, 2026

Memory corruption in affected Linux Kernel releases allows local users to corrupt GPU-buffer data through crafted VCN submissions. The VCN 2.0 encoder and decoder ring definitions omit no_user_fence, so AMDGPU accepts an unsupported 64-bit fence write and the decoder truncates its address. Access to a VCN 2.0-capable AMDGPU render node is required; reported consequences include buffer corruption or disclosure, a video-engine hang, and a GPU reset.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in affected Linux Kernel releases allows local users to corrupt GPU-buffer data through crafted VCN submissions. The VCN 2.0 encoder and decoder ring definitions omit no_user_fence, so AMDGPU accepts an unsupported 64-bit fence write and the decoder truncates its address. Access to a VCN 2.0-capable AMDGPU render node is required; reported consequences include buffer corruption or disclosure, a video-engine hang, and a GPU reset.

The record

CVE
CVE-2026-63856
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
Unavailable

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

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Is a vulnerable build present?

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

  1. Affected versionversion=1b61de45dfaff00b627e47349a019658e39268b9 <5e777bc4cbe928ac0fd95e368fee1540f2ce4db2
  2. Affected versionversion=1b61de45dfaff00b627e47349a019658e39268b9 <8d80b293b41fcb5e9396db93e788b0f4ebcbafb7
  3. Affected versionversion=1b61de45dfaff00b627e47349a019658e39268b9 <ac06ce5cac9e711281585d09d00c6efcd9b86396
  4. Affected versionversion=1b61de45dfaff00b627e47349a019658e39268b9 <c71aecae98e42dcf2baf462df50b3a2cf1a93fe4
  5. Affected versionversion=1b61de45dfaff00b627e47349a019658e39268b9 <f264019be80de79f84f464846451445923bffea0
  6. Affected versionversion=5.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1b61de45dfaff00b627e47349a019658e39268b9 <5e777bc4cbe928ac0fd95e368fee1540f2ce4db2; version=1b61de45dfaff00b627e47349a019658e39268b9 <8d80b293b41fcb5e9396db93e788b0f4ebcbafb7; version=1b61de45dfaff00b627e47349a019658e39268b9 <ac06ce5cac9e711281585d09d00c6efcd9b86396; version=1b61de45dfaff00b627e47349a019658e39268b9 <c71aecae98e42dcf2baf462df50b3a2cf1a93fe4; version=1b61de45dfaff00b627e47349a019658e39268b9 <f264019be80de79f84f464846451445923bffea0; version=5.3

Published CVSS scores

7.8kernel.orgCVSS: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.

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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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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