CVE-2021-39669

Local privilege escalation via certificate-warning tapjacking

Published Feb 11, 2022 · Updated Aug 4, 2024

Tapjacking in Android 11 and Android 12 allows local users to escalate privileges by overlaying the CA certificate installation warning. InstallCaCertificateWarning.onCreate leaves non-system overlay windows visible while presenting the confirmation UI, allowing a malicious overlay to misrepresent the certificate installation circumstances. Exploitation requires user interaction with the obscured warning; the documented consequence is local privilege escalation through a misleading CA-installation approval.

CVSS severity7.8
High
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Tapjacking in Android 11 and Android 12 allows local users to escalate privileges by overlaying the CA certificate installation warning. InstallCaCertificateWarning.onCreate leaves non-system overlay windows visible while presenting the confirmation UI, allowing a malicious overlay to misrepresent the certificate installation circumstances. Exploitation requires user interaction with the obscured warning; the documented consequence is local privilege escalation through a misleading CA-installation approval.

The record

CVE
CVE-2021-39669
Published
Feb 11, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-1021, T1417.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 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-11 Android-12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Google Cloud · Androidversion=Android-11 Android-12

Published CVSS scores

4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1021Improper Restriction of Rendered UI Layers or Frames
T1417.002Input Capture: GUI Input Capture

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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