CVE-2021-39749Public exploit

Local privilege escalation via cleared caller identity

Published Mar 30, 2022 · Updated Aug 4, 2024

Missing authorization in Android 12L WindowManager allows local users to start protected activities without user interaction. ActivityStartController.startActivityInTaskFragment checks Binder.getCallingUid after Binder.clearCallingIdentity, treating an app-originated request as the system UID and bypassing exported and permission restrictions. A locally installed app can use TaskFragmentOrganizer transactions to launch another app's non-exported or permission-protected activity, enabling privilege escalation without additional execution privileges.

CVSS severity7.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Android 12L WindowManager allows local users to start protected activities without user interaction. ActivityStartController.startActivityInTaskFragment checks Binder.getCallingUid after Binder.clearCallingIdentity, treating an app-originated request as the system UID and bypassing exported and permission restrictions. A locally installed app can use TaskFragmentOrganizer transactions to launch another app's non-exported or permission-protected activity, enabling privilege escalation without additional execution privileges.

The record

CVE
CVE-2021-39749
Published
Mar 30, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-862, T1626
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 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-12L

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-12L

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 exploitPublished

Weakness, pattern, technique

CWE-862Missing Authorization
T1626Abuse Elevation Control Mechanism

Public exploit references

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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