CVE-2021-0538

Emergency callback mode exit via overlaid dialog

Published Jun 22, 2021 · Updated Aug 3, 2024

Tapjacking in Android 11's emergency callback mode exit dialog allows local users to exit the mode through a disguised tap. The dialog's onCreate method fails to set SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS, allowing a third-party overlay to conceal the affirmative control while forwarding a user's tap to exitEmergencyCallbackMode(). Exploitation requires User-level code, an active emergency callback session, and user interaction; the result is unauthorized termination of that protected mode.

CVSS severity7.3
High
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

Tapjacking in Android 11's emergency callback mode exit dialog allows local users to exit the mode through a disguised tap. The dialog's onCreate method fails to set SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS, allowing a third-party overlay to conceal the affirmative control while forwarding a user's tap to exitEmergencyCallbackMode(). Exploitation requires User-level code, an active emergency callback session, and user interaction; the result is unauthorized termination of that protected mode.

The record

CVE
CVE-2021-0538
Published
Jun 22, 2021
Updated
Aug 3, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-1021, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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-11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-11

Published CVSS scores

7.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
4.4NVDAV:L/AC:M/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 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

CWE-1021Improper Restriction of Rendered UI Layers or Frames
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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