CVE-2021-39703

Local privilege escalation via delayed USB disconnect

Published Mar 16, 2022 · Updated Aug 4, 2024

Confused-deputy flaw in Android 12 System allows local users to gain elevated file access through USB state changes. The UsbDeviceManager.updateState method extends disconnect processing to three seconds while the screen is unlocked, leaving stale MTP authorization during a rapid replug. Exploitation requires local access to drive USB state changes, needs no user interaction, and exposes files beyond the caller's authorization.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Confused-deputy flaw in Android 12 System allows local users to gain elevated file access through USB state changes. The UsbDeviceManager.updateState method extends disconnect processing to three seconds while the screen is unlocked, leaving stale MTP authorization during a rapid replug. Exploitation requires local access to drive USB state changes, needs no user interaction, and exposes files beyond the caller's authorization.

The record

CVE
CVE-2021-39703
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-610, T1404
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 16, 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-12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-12

Published CVSS scores

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

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-610Externally Controlled Reference to a Resource in Another Sphere
T1404Exploitation 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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