CVE-2021-46934

Kernel warning via unvalidated compat I2C messages

Published Feb 27, 2024 · Updated May 11, 2026

Improper input validation in Linux kernel 4.15 through 5.15.12 allows local users to trigger a warning through a compat I2C_RDWR ioctl. The compat_i2cdev_ioctl function copies the user-supplied transfer structure but fails to reject a null message pointer or zero message count before invoking i2c_transfer. Access to an I2C device and the 32-bit compatibility ioctl path is required; upstream evidence reports a kernel warning, not a crash or code execution.

CVSS severity3.3
Low
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

Improper input validation in Linux kernel 4.15 through 5.15.12 allows local users to trigger a warning through a compat I2C_RDWR ioctl. The compat_i2cdev_ioctl function copies the user-supplied transfer structure but fails to reject a null message pointer or zero message count before invoking i2c_transfer. Access to an I2C device and the 32-bit compatibility ioctl path is required; upstream evidence reports a kernel warning, not a crash or code execution.

The record

CVE
CVE-2021-46934
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-754
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

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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=4.15
  2. Affected versionversion=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <407c8708fb1bf2d4afc5337ef50635cf540c364b
  3. Affected versionversion=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <8d31cbab4c295d7010ebb729e9d02d0e9cece18f
  4. Affected versionversion=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <9e4a3f47eff476097e0c7faac04d1831fc70237d
  5. Affected versionversion=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <bb436283e25aaf1533ce061605d23a9564447bdf
  6. Affected versionversion=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <f68599581067e8a5a8901ba9eb270b4519690e26

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <407c8708fb1bf2d4afc5337ef50635cf540c364b; version=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <8d31cbab4c295d7010ebb729e9d02d0e9cece18f; version=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <9e4a3f47eff476097e0c7faac04d1831fc70237d; version=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <bb436283e25aaf1533ce061605d23a9564447bdf; version=7d5cb45655f2e9e37ef75d18f50c0072ef14a38b <f68599581067e8a5a8901ba9eb270b4519690e26

Published CVSS scores

4.4Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
3.3NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
4.4Oracle LinuxCVSS:3.0/AV:L/AC:L/PR:H/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-754Improper Check for Unusual or Exceptional Conditions

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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