CVE-2021-39719

Local privilege escalation via integer-overflow write

Published Mar 16, 2022 · Updated Aug 4, 2024

Out-of-bounds write in the Android kernel allows local users with System execution privileges to escalate privileges without user interaction. The lwis_top_register_io function in lwis_device_top.c uses an integer calculation that can overflow, causing a write to exceed its intended bounds. Exploitation requires local access and System execution privileges; successful memory corruption grants higher privilege without user interaction.

CVSS severity6.7
Medium
EPSS probability0.11%
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 Android kernel allows local users with System execution privileges to escalate privileges without user interaction. The lwis_top_register_io function in lwis_device_top.c uses an integer calculation that can overflow, causing a write to exceed its intended bounds. Exploitation requires local access and System execution privileges; successful memory corruption grants higher privilege without user interaction.

The record

CVE
CVE-2021-39719
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-190, CWE-787, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Mar 16, 2022CVE 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?

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  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google Cloud · Androidversion=Android kernel

Published CVSS scores

6.7NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

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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