CVE-2021-47197

Host crash via stale debugfs pointer reuse

Published Apr 10, 2024 · Updated Aug 5, 2026

Resource teardown flaw in the Linux kernel mlx5 driver allows local users to crash the host by repeatedly destroying a completion queue. mlx5_debug_cq_remove() removes cq->dbg but leaves the pointer non-null, so a second mlx5_core_destroy_cq() call after a failed firmware command reuses it during debugfs removal. Local access to mlx5 userspace verbs and a failed firmware destroy command are required; the demonstrated consequence is a kernel crash.

CVSS severity7.8
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource teardown flaw in the Linux kernel mlx5 driver allows local users to crash the host by repeatedly destroying a completion queue. mlx5_debug_cq_remove() removes cq->dbg but leaves the pointer non-null, so a second mlx5_core_destroy_cq() call after a failed firmware command reuses it during debugfs removal. Local access to mlx5 userspace verbs and a failed firmware destroy command are required; the demonstrated consequence is a kernel crash.

The record

CVE
CVE-2021-47197
Published
Apr 10, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 10, 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=4f7bddf8c5c01cac74373443b13a68e1c6723a94 <471c492890557bd58f73314bb4ad85d5a8fd5026
  2. Affected versionversion=5.10.75 <5.10.82
  3. Affected versionversion=5.14.14 <5.15
  4. Affected versionversion=5.15
  5. Affected versionversion=94b960b9deffc02fc0747afc01f72cc62ab099e3 <2ae38157080616a13a9fe3f0b4b6ec0070aa408a
  6. Affected versionversion=94b960b9deffc02fc0747afc01f72cc62ab099e3 <76ded29d3fcda4928da8849ffc446ea46871c1c2
  7. Affected versionversion=ed8aafea4fec9c654e63445236e0b505e27ed3a7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4f7bddf8c5c01cac74373443b13a68e1c6723a94 <471c492890557bd58f73314bb4ad85d5a8fd5026; version=5.10.75 <5.10.82; version=5.14.14 <5.15; version=5.15; version=94b960b9deffc02fc0747afc01f72cc62ab099e3 <2ae38157080616a13a9fe3f0b4b6ec0070aa408a; version=94b960b9deffc02fc0747afc01f72cc62ab099e3 <76ded29d3fcda4928da8849ffc446ea46871c1c2; version=ed8aafea4fec9c654e63445236e0b505e27ed3a7

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NIST NVDCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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