CVE-2021-31916Public exploit

Kernel crash via undersized device-list buffer

Published May 6, 2021 · Updated Aug 3, 2024

Out-of-bounds write in the Linux Kernel before 5.12 allows local users with CAP_SYS_ADMIN to crash the system via DM_LIST_DEVICES_CMD. When no device-mapper devices exist, list_devices accepts a result buffer smaller than nl->dev and still clears that field beyond the allocation. Root-equivalent local privilege is required; the overwrite can crash the host or disclose internal kernel memory.

CVSS severity6.7
Medium
EPSS probability0.70%
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 before 5.12 allows local users with CAP_SYS_ADMIN to crash the system via DM_LIST_DEVICES_CMD. When no device-mapper devices exist, list_devices accepts a result buffer smaller than nl->dev and still clears that field beyond the allocation. Root-equivalent local privilege is required; the overwrite can crash the host or disclose internal kernel memory.

The record

CVE
CVE-2021-31916
Published
May 6, 2021
Updated
Aug 3, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Kernel 5.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Kernel 5.12

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.1NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:C

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 exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

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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