CVE-2022-20536

Local privilege escalation via unprotected TTY broadcast

Published Dec 16, 2022 · Updated Apr 18, 2025

Missing authorization in RcsService in Android 13 allows local users to change the preferred TTY mode via an unprotected broadcast. The registerBroadcastReceiver method registers ACTION_TTY_PREFERRED_MODE_CHANGED without requiring MODIFY_PHONE_STATE, so broadcasts from unprivileged apps reach its receiver. Any local app can alter the telephony accessibility setting without user interaction; the demonstrated consequence is limited to unauthorized TTY-mode changes.

CVSS severity3.3
Low
EPSS probability0.11%
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 RcsService in Android 13 allows local users to change the preferred TTY mode via an unprotected broadcast. The registerBroadcastReceiver method registers ACTION_TTY_PREFERRED_MODE_CHANGED without requiring MODIFY_PHONE_STATE, so broadcasts from unprivileged apps reach its receiver. Any local app can alter the telephony accessibility setting without user interaction; the demonstrated consequence is limited to unauthorized TTY-mode changes.

The record

CVE
CVE-2022-20536
Published
Dec 16, 2022
Updated
Apr 18, 2025
Vendor
Google Cloud
Product
Android
Classifications
CWE-862
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 18, 2025Record 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-13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-13

Published CVSS scores

3.3NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
3.3CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

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

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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