CVE-2021-46979

Kernel panic via duplicate ioctl handler removal

Published Feb 28, 2024 · Updated May 11, 2026

A double free in Linux kernel IIO core 5.11, 5.12, and 5.13-rc1 allows local users to panic the kernel during device unregistration. iio_device_unregister removes ioctl handlers directly, after which event-set and buffer cleanup paths remove the same handlers again. Low-privileged local access is required, and the public record does not identify the specific user action or device configuration needed to reach unregistration.

CVSS severity5.5
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A double free in Linux kernel IIO core 5.11, 5.12, and 5.13-rc1 allows local users to panic the kernel during device unregistration. iio_device_unregister removes ioctl handlers directly, after which event-set and buffer cleanup paths remove the same handlers again. Low-privileged local access is required, and the public record does not identify the specific user action or device configuration needed to reach unregistration.

The record

CVE
CVE-2021-46979
Published
Feb 28, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-415, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 28, 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=5.11
  2. Affected versionversion=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <11e1cae5da4096552f7c091476cbadbc0d1817da
  3. Affected versionversion=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <901f84de0e16bde10a72d7eb2f2eb73fcde8fa1a
  4. Affected versionversion=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <ab6c935ba3a04317632f3b8b68675bdbaf395303

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.11; version=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <11e1cae5da4096552f7c091476cbadbc0d1817da; version=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <901f84de0e16bde10a72d7eb2f2eb73fcde8fa1a; version=8dedcc3eee3aceb37832176f0a1b03d5687acda3 <ab6c935ba3a04317632f3b8b68675bdbaf395303

Published CVSS scores

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

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-415Double Free
T1499Endpoint Denial of Service

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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