CVE-2021-39734

Local privilege escalation via unchecked RCS messaging permission

Published Mar 16, 2022 · Updated Aug 4, 2024

Missing authorization in Android's Telephony component allows local users to send RCS messages without the required permission. The sendMessage method in OneToOneChatImpl.java dispatches an RCS message without first verifying the caller's messaging permission. Exploitation requires a local user or application context, needs no user interaction, and can send messages under telephony-service authority.

CVSS severity7.8
High
EPSS probability0.10%
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's Telephony component allows local users to send RCS messages without the required permission. The sendMessage method in OneToOneChatImpl.java dispatches an RCS message without first verifying the caller's messaging permission. Exploitation requires a local user or application context, needs no user interaction, and can send messages under telephony-service authority.

The record

CVE
CVE-2021-39734
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-862, 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?

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  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android kernel

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P

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-862Missing Authorization
T1404Exploitation for Privilege Escalation

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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