CVE-2021-47551

Kernel crash via repeated KFD teardown

Published May 24, 2024 · Updated Aug 5, 2026

Use-after-free in the AMD KFD scheduler in Linux 5.5 and later allows local users to crash the kernel through repeated failed GPU resets. In SR-IOV mode, a failed reset stops CPSCH without restarting it, and a later reset calls stop_cpsch again, reusing freed fence and packet-manager state. Access to /dev/kfd or a DRM render node and an AMD SR-IOV GPU are required; the second teardown can panic the affected kernel.

CVSS severity7.8
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in the AMD KFD scheduler in Linux 5.5 and later allows local users to crash the kernel through repeated failed GPU resets. In SR-IOV mode, a failed reset stops CPSCH without restarting it, and a later reset calls stop_cpsch again, reusing freed fence and packet-manager state. Access to /dev/kfd or a DRM render node and an AMD SR-IOV GPU are required; the second teardown can panic the affected kernel.

The record

CVE
CVE-2021-47551
Published
May 24, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-770, T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 24, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2c99a547bcf9bb8532abd2953479949018449f93 <06c6f8f86ec243b89e52f0c3dc7062bcb9de74df
  2. Affected versionversion=2c99a547bcf9bb8532abd2953479949018449f93 <2cf49e00d40d5132e3d067b5aa6d84791929ab15
  3. Affected versionversion=2c99a547bcf9bb8532abd2953479949018449f93 <74aafe99efb68f15e50be9f7032c2168512f98a8
  4. Affected versionversion=5.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2c99a547bcf9bb8532abd2953479949018449f93 <06c6f8f86ec243b89e52f0c3dc7062bcb9de74df; version=2c99a547bcf9bb8532abd2953479949018449f93 <2cf49e00d40d5132e3d067b5aa6d84791929ab15; version=2c99a547bcf9bb8532abd2953479949018449f93 <74aafe99efb68f15e50be9f7032c2168512f98a8; version=5.5

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
7.8Linux kernel security teamCVSS: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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo