CVE-2021-4460

Local disclosure and interruption via SDMA shift

Published Oct 1, 2025 · Updated Oct 1, 2025

Out-of-bounds read in the Linux kernel allows local users to read memory or interrupt service through the AMD KFD queue manager. When either queue-count helper returns zero, kfd_device_queue_manager.c shifts an operand by its full bit width while building the SDMA queue mask, producing undefined behavior. Reachability requires local low-privileged access and an AMD GPU configuration that reports zero SDMA or XGMI SDMA queues; impact is limited to memory disclosure and service interruption.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux kernel allows local users to read memory or interrupt service through the AMD KFD queue manager. When either queue-count helper returns zero, kfd_device_queue_manager.c shifts an operand by its full bit width while building the SDMA queue mask, producing undefined behavior. Reachability requires local low-privileged access and an AMD GPU configuration that reports zero SDMA or XGMI SDMA queues; impact is limited to memory disclosure and service interruption.

The record

CVE
CVE-2021-4460
Published
Oct 1, 2025
Updated
Oct 1, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 1, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2025Record 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0c0356ef2498c1a250fe3846f30293f828737309
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1874b0ef1426b873de94c61861e38f29a8df714c
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3fdc5182700910a685d23df57d65166e8556a266
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <50e2fc36e72d4ad672032ebf646cecb48656efe0
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9069b1b542de8f3bbffef868aff41521b21485cf

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <0c0356ef2498c1a250fe3846f30293f828737309; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <1874b0ef1426b873de94c61861e38f29a8df714c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3fdc5182700910a685d23df57d65166e8556a266; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <50e2fc36e72d4ad672032ebf646cecb48656efe0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9069b1b542de8f3bbffef868aff41521b21485cf

Published CVSS scores

7.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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

CWE-125Out-of-bounds Read

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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