CVE-2021-0658

Local privilege escalation via unchecked buffer write

Published Nov 18, 2021 · Updated Aug 3, 2024

An out-of-bounds write in MediaTek APUSYS on Android 10.0 and 11.0 allows local users with System privileges to escalate privileges. MediaTek identifies only APUSYS as the locus; the affected function and input path are not public, but the write lacks a destination-bounds check. Exploitation requires prior System execution privileges on an affected MediaTek chipset, needs no user interaction, and has no published remote path.

CVSS severity6.7
Medium
EPSS probability0.12%
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 APUSYS on Android 10.0 and 11.0 allows local users with System privileges to escalate privileges. MediaTek identifies only APUSYS as the locus; the affected function and input path are not public, but the write lacks a destination-bounds check. Exploitation requires prior System execution privileges on an affected MediaTek chipset, needs no user interaction, and has no published remote path.

The record

CVE
CVE-2021-0658
Published
Nov 18, 2021
Updated
Aug 3, 2024
Vendor
MediaTek
Product
MediaTek APUSYS
Classifications
CWE-119, T1404
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Nov 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 10.0, 11.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

MediaTek · MediaTek APUSYSversion=Android 10.0, 11.0

Published CVSS scores

4.6NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
6.7NVDCVSS: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-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1404Exploitation 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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