CVE-2021-39670

Permanent denial of service via oversized wallpaper input

Published May 10, 2022 · Updated Aug 4, 2024

Denial of service in Android 12 and Android 12L allows local users to make a device permanently unavailable through wallpaper input. WallpaperManager.setStream copies an oversized image stream to the wallpaper path before validating it, allowing system_server to exhaust memory. A local app with User execution privileges and SET_WALLPAPER permission can trigger the condition without user interaction, resulting in a permanent service interrupt.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Android 12 and Android 12L allows local users to make a device permanently unavailable through wallpaper input. WallpaperManager.setStream copies an oversized image stream to the wallpaper path before validating it, allowing system_server to exhaust memory. A local app with User execution privileges and SET_WALLPAPER permission can trigger the condition without user interaction, resulting in a permanent service interrupt.

The record

CVE
CVE-2021-39670
Published
May 10, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-770, T1642
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 10, 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 Android-12L

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-12 Android-12L

Published CVSS scores

4.9NIST National Vulnerability DatabaseAV:L/AC:L/Au:N/C:N/I:N/A:C
5.5NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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

CWE-770Allocation of Resources Without Limits or Throttling
T1642Endpoint Denial of Service

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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