CVE-2021-43975

Kernel memory corruption via unchecked RPC length

Published Nov 17, 2021 · Updated Aug 4, 2024

Out-of-bounds write in the Linux kernel through 5.15.2 allows local users to corrupt kernel memory through a crafted device. The Atlantic driver's hw_atl_utils_fw_rpc_wait function trusts device-supplied RPC length fields and transfers more data than the fixed self->rpc buffer can hold. Exploitation requires control of a compromised, malfunctioning, or emulated networking device and can crash the host; the upstream report also demonstrated an out-of-bounds read before the overwrite.

CVSS severity6.7
Medium
EPSS probability0.55%
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 through 5.15.2 allows local users to corrupt kernel memory through a crafted device. The Atlantic driver's hw_atl_utils_fw_rpc_wait function trusts device-supplied RPC length fields and transfers more data than the fixed self->rpc buffer can hold. Exploitation requires control of a compromised, malfunctioning, or emulated networking device and can crash the host; the upstream report also demonstrated an out-of-bounds read before the overwrite.

The record

CVE
CVE-2021-43975
Published
Nov 17, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1200
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 17, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.6NIST National Vulnerability DatabaseAV:L/AC:L/Au:N/C:P/I:P/A:P
6.7UbuntuCVSS:3.1/AV:L/AC:L/PR:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1200Hardware Additions

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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