CVE-2021-39653

Local privilege escalation via hidden debug policy

Published Dec 15, 2021 · Updated Aug 4, 2024

Bootloader elevation of privilege in Google Pixel devices with the Android kernel allows local users to gain elevated privileges. The bootloader permits a debug policy to remain hidden because it fails to display the required warning before boot. Exploitation requires physical preparation of the device and concealment of the warning before the phone is transferred to another user; Google has not published further technical detail.

CVSS severity7.8
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Bootloader elevation of privilege in Google Pixel devices with the Android kernel allows local users to gain elevated privileges. The bootloader permits a debug policy to remain hidden because it fails to display the required warning before boot. Exploitation requires physical preparation of the device and concealment of the warning before the phone is transferred to another user; Google has not published further technical detail.

The record

CVE
CVE-2021-39653
Published
Dec 15, 2021
Updated
Aug 4, 2024
Vendor
Google
Product
Google Pixel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 15, 2021CVE 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 privilegesauthenticated

What is affected?

Google · Google Pixelversion=Android kernel

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/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.

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

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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