CVE-2023-21135

Local privilege escalation via overlong component names

Published Jun 15, 2023 · Updated Dec 18, 2024

Improper input validation in Android 11, 12, 12L, and 13 allows local users to escalate privileges through notification-listener settings. NotificationAccessSettings accepts notification-listener components whose flattened names exceed the Settings limit, while NotificationManagerService fails to enforce that limit when granting access. A malicious local application can exploit the inconsistent validation without user interaction or additional execution privileges, obtaining unauthorized notification-listener access.

CVSS severity7.8
High
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Android 11, 12, 12L, and 13 allows local users to escalate privileges through notification-listener settings. NotificationAccessSettings accepts notification-listener components whose flattened names exceed the Settings limit, while NotificationManagerService fails to enforce that limit when granting access. A malicious local application can exploit the inconsistent validation without user interaction or additional execution privileges, obtaining unauthorized notification-listener access.

The record

CVE
CVE-2023-21135
Published
Jun 15, 2023
Updated
Dec 18, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-120, CWE-20, T1404
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 18, 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-11 Android-12 Android-12L Android-13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android-11 Android-12 Android-12L Android-13

Published CVSS scores

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
CWE-20Improper Input Validation
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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