CVE-2021-39799

Local privilege escalation via spoofed attribution PID

Published Apr 12, 2022 · Updated Aug 4, 2024

Improper input validation in Android 12 and 12L AttributionSource allows local users to bypass permission checks and gain privileges. When AttributionSource is unmarshaled from a Binder Parcel, its constructor validates the claimed UID but fails to verify that the claimed PID matches Binder.getCallingPid(), allowing process-attribution spoofing. Exploitation requires local app execution, needs no user interaction, and grants access protected by permissions attributed to another process.

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

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper input validation in Android 12 and 12L AttributionSource allows local users to bypass permission checks and gain privileges. When AttributionSource is unmarshaled from a Binder Parcel, its constructor validates the claimed UID but fails to verify that the claimed PID matches Binder.getCallingPid(), allowing process-attribution spoofing. Exploitation requires local app execution, needs no user interaction, and grants access protected by permissions attributed to another process.

The record

CVE
CVE-2021-39799
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-863, T1068
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

7.8NIST National Vulnerability DatabaseCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NIST National Vulnerability DatabaseAV: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-863Incorrect Authorization
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo