CVE-2021-47280Public exploit

Local kernel crash via DRM master-pointer race

Published May 21, 2024 · Updated May 11, 2026

Use-after-free in affected Linux kernel builds from 4.11 through 5.13-rc5 allows local users to crash the kernel via concurrent DRM ioctls. drm_getunique reads file_priv->master before acquiring dev->master_mutex, so drm_setmaster_ioctl can replace and free that master while the first thread still dereferences it. Exploitation requires low-privileged local access to a DRM device and winning the race; the demonstrated consequence is a KASAN-detected kernel memory read and resulting service interruption.

CVSS severity7.0
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux kernel builds from 4.11 through 5.13-rc5 allows local users to crash the kernel via concurrent DRM ioctls. drm_getunique reads file_priv->master before acquiring dev->master_mutex, so drm_setmaster_ioctl can replace and free that master while the first thread still dereferences it. Exploitation requires low-privileged local access to a DRM device and winning the race; the demonstrated consequence is a KASAN-detected kernel memory read and resulting service interruption.

The record

CVE
CVE-2021-47280
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, CWE-367, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=4.11
  2. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <17dab9326ff263c62dab1dbac4492e2938a049e4
  3. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <491d52e0078860b33b6c14f0a7ac74ca1b603bd6
  4. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <7d233ba700ceb593905ea82b42dadb4ec8ef85e9
  5. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <b246b4c70c1250e7814f409b243000f9c0bf79a3
  6. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <b436acd1cf7fac0ba987abd22955d98025c80c2b
  7. Affected versionversion=5acc614ac47465fee6375a9af4740f618830762d <f773f8cccac13c7e7bbd9182e7996c727742488e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=5acc614ac47465fee6375a9af4740f618830762d <17dab9326ff263c62dab1dbac4492e2938a049e4; version=5acc614ac47465fee6375a9af4740f618830762d <491d52e0078860b33b6c14f0a7ac74ca1b603bd6; version=5acc614ac47465fee6375a9af4740f618830762d <7d233ba700ceb593905ea82b42dadb4ec8ef85e9; version=5acc614ac47465fee6375a9af4740f618830762d <b246b4c70c1250e7814f409b243000f9c0bf79a3; version=5acc614ac47465fee6375a9af4740f618830762d <b436acd1cf7fac0ba987abd22955d98025c80c2b; version=5acc614ac47465fee6375a9af4740f618830762d <f773f8cccac13c7e7bbd9182e7996c727742488e

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1499.004Application or System Exploitation

Public exploit references

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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