CVE-2021-46931

Kernel panic via mlx5e callback type confusion

Published Feb 27, 2024 · Updated May 11, 2026

Out-of-bounds write in the Linux kernel mlx5e driver beginning in 5.7 allows local users to trigger a kernel panic. The TX-timeout recovery path passes a mlx5e_tx_timeout_ctx pointer to mlx5e_tx_reporter_dump_sq(), which wrongly treats it as mlx5e_txqsq and overruns the kernel stack. Low-privileged local access and an mlx5e transmit-queue timeout are required; the resulting fatal exception terminates the host.

CVSS severity5.5
Medium
EPSS probability0.24%
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 write in the Linux kernel mlx5e driver beginning in 5.7 allows local users to trigger a kernel panic. The TX-timeout recovery path passes a mlx5e_tx_timeout_ctx pointer to mlx5e_tx_reporter_dump_sq(), which wrongly treats it as mlx5e_txqsq and overruns the kernel stack. Low-privileged local access and an mlx5e transmit-queue timeout are required; the resulting fatal exception terminates the host.

The record

CVE
CVE-2021-46931
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1529
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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

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=5.7
  2. Affected versionversion=5f29458b77d51c104554575b73184c243930aa87 <07f13d58a8ecc3baf9a488588fb38c5cb0db484f
  3. Affected versionversion=5f29458b77d51c104554575b73184c243930aa87 <73665165b64a8f3c5b3534009a69be55bb744f05
  4. Affected versionversion=5f29458b77d51c104554575b73184c243930aa87 <918fc3855a6507a200e9cf22c20be852c0982687

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=5f29458b77d51c104554575b73184c243930aa87 <07f13d58a8ecc3baf9a488588fb38c5cb0db484f; version=5f29458b77d51c104554575b73184c243930aa87 <73665165b64a8f3c5b3534009a69be55bb744f05; version=5f29458b77d51c104554575b73184c243930aa87 <918fc3855a6507a200e9cf22c20be852c0982687

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Canonical UbuntuCVSS: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

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 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-787Out-of-bounds Write
T1529System Shutdown/Reboot

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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