CVE-2021-39798

Local privilege escalation via oversized Bitmap Parcel

Published Apr 12, 2022 · Updated Aug 4, 2024

Out-of-bounds write in Android 12 and 12L Bitmap_createFromParcel allows local users to execute code and elevate privileges via a crafted Parcel. The function allocates pixel storage from rowBytes and height but copied an attacker-controlled blob length without ensuring the copy fit the allocation. A user-level process can trigger the flaw without user interaction, corrupt heap memory, and execute code in a more privileged process.

CVSS severity7.8
High
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Android 12 and 12L Bitmap_createFromParcel allows local users to execute code and elevate privileges via a crafted Parcel. The function allocates pixel storage from rowBytes and height but copied an attacker-controlled blob length without ensuring the copy fit the allocation. A user-level process can trigger the flaw without user interaction, corrupt heap memory, and execute code in a more privileged process.

The record

CVE
CVE-2021-39798
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-119, T1404
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 12, 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

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.

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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
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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