CVE-2021-47541

Kernel memory corruption via unchecked copy failure

Published May 24, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux mlx4_en driver from 4.7 allows local users to corrupt kernel memory during resource reallocation. mlx4_en_try_alloc_resources ignores a mlx4_en_copy_priv failure after that failure frees tmp->tx_cq, then mlx4_en_alloc_resources dereferences the freed array. The path requires local access, an active mlx4_en configuration, and a copy failure; the issue was identified by static analysis and is documented as hard to trigger.

CVSS severity7.8
High
EPSS probability0.29%
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 the Linux mlx4_en driver from 4.7 allows local users to corrupt kernel memory during resource reallocation. mlx4_en_try_alloc_resources ignores a mlx4_en_copy_priv failure after that failure frees tmp->tx_cq, then mlx4_en_alloc_resources dereferences the freed array. The path requires local access, an active mlx4_en configuration, and a copy failure; the issue was identified by static analysis and is documented as hard to trigger.

The record

CVE
CVE-2021-47541
Published
May 24, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

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

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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=4.7
  2. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <676dc7d9b15bf8733233a2db1ec3f9091ab34275
  3. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <75917372eef0dbfb290ae45474314d35f97aea18
  4. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <addad7643142f500080417dd7272f49b7a185570
  5. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <be12572c5ddc8ad7453bada4eec8fa46967dc757
  6. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <e461a9816a1ac5b4aeb61621b817225b61e46a68
  7. Affected versionversion=ec25bc04ed8e12947738468cbe2191f1529f9e39 <f1d43efa59f1edd3e7eca0e94559b4c6b1cd4e2b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.7; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <676dc7d9b15bf8733233a2db1ec3f9091ab34275; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <75917372eef0dbfb290ae45474314d35f97aea18; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <addad7643142f500080417dd7272f49b7a185570; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <be12572c5ddc8ad7453bada4eec8fa46967dc757; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <e461a9816a1ac5b4aeb61621b817225b61e46a68; version=ec25bc04ed8e12947738468cbe2191f1529f9e39 <f1d43efa59f1edd3e7eca0e94559b4c6b1cd4e2b

Published CVSS scores

7.8NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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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