CVE-2023-20694

Local privilege escalation via unchecked preloader write

Published May 15, 2023 · Updated Jan 23, 2025

An out-of-bounds write in MediaTek preloader on Android 12.0 and 13.0 and OpenWrt 19.07 and 21.02 allows local users to elevate privilege. The preloader fails to bounds-check input before writing it, permitting data to be written beyond the intended buffer. Exploitation requires existing System execution privileges but no user interaction, and successful use elevates local privilege.

CVSS severity6.7
Medium
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

An out-of-bounds write in MediaTek preloader on Android 12.0 and 13.0 and OpenWrt 19.07 and 21.02 allows local users to elevate privilege. The preloader fails to bounds-check input before writing it, permitting data to be written beyond the intended buffer. Exploitation requires existing System execution privileges but no user interaction, and successful use elevates local privilege.

The record

CVE
CVE-2023-20694
Published
May 15, 2023
Updated
Jan 23, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, CWE-20, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 23, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7CISA-ADPCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-20Improper Input Validation
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

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Your stack

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