CVE-2021-39731

Local privilege escalation via incorrect bounds check

Published Mar 16, 2022 · Updated Aug 4, 2024

Out-of-bounds write in Google Pixel Android kernel Telephony allows local users with System privileges to escalate privilege. ProtocolStkProactiveCommandAdapter::Init applies an incorrect bounds check and can write beyond its destination buffer. Exploitation requires existing System execution privileges on a Pixel device, needs no user interaction, and grants elevated local privileges.

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 Google Pixel Android kernel Telephony allows local users with System privileges to escalate privilege. ProtocolStkProactiveCommandAdapter::Init applies an incorrect bounds check and can write beyond its destination buffer. Exploitation requires existing System execution privileges on a Pixel device, needs no user interaction, and grants elevated local privileges.

The record

CVE
CVE-2021-39731
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google
Product
Google Pixel
Classifications
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?

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

  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google · Google Pixelversion=Android kernel

Published CVSS scores

6.7NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
4.6NIST National Vulnerability DatabaseAV: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
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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