CVE-2021-39729

System privilege escalation via out-of-bounds write

Published Mar 16, 2022 · Updated Aug 4, 2024

Out-of-bounds write in Google Titan M on affected Android kernels allows local users with System execution privileges to escalate privileges. A missing bounds check permits a write past the intended memory boundary inside the chip; Google has not disclosed the affected routine. Exploitation requires local access with existing System execution privileges, requires no user interaction, and yields higher privileges on the Pixel device.

CVSS severity6.7
Medium
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

Out-of-bounds write in Google Titan M on affected Android kernels allows local users with System execution privileges to escalate privileges. A missing bounds check permits a write past the intended memory boundary inside the chip; Google has not disclosed the affected routine. Exploitation requires local access with existing System execution privileges, requires no user interaction, and yields higher privileges on the Pixel device.

The record

CVE
CVE-2021-39729
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google
Product
Titan M
Classifications
CWE-787, T1404
Attack vector
local
Privileges
admin

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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google · Titan Mversion=Android kernel

Published CVSS scores

6.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
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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