CVE-2021-39678

Local privilege escalation through Factory Reset Protection bypass

Published Jan 14, 2022 · Updated Aug 4, 2024

Privilege escalation in Google Gboard on supported Pixel devices allows local users to bypass Factory Reset Protection without interaction. The private Android issue does not disclose the Gboard or kernel locus or the operation that defeats the reset-protection check. Exploitation requires low-privileged local access and can defeat post-reset account verification while elevating privileges.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in Google Gboard on supported Pixel devices allows local users to bypass Factory Reset Protection without interaction. The private Android issue does not disclose the Gboard or kernel locus or the operation that defeats the reset-protection check. Exploitation requires low-privileged local access and can defeat post-reset account verification while elevating privileges.

The record

CVE
CVE-2021-39678
Published
Jan 14, 2022
Updated
Aug 4, 2024
Vendor
Google
Product
Gboard
Classifications
T1626
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 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 privilegesauthenticated

What is affected?

Google · Gboardversion=Android kernel

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

T1626Abuse Elevation Control Mechanism

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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