CVE-2021-39725

Local privilege escalation via coherent-memory double free

Published Mar 16, 2022 · Updated Aug 4, 2024

Double free in the Android kernel allows local users with System execution privileges to elevate privileges without user interaction. The gasket_free_coherent_memory_all function in gasket_page_table.c releases coherent-memory bookkeeping twice, corrupting kernel memory. Exploitation requires local code already running with System execution privileges and grants higher kernel-backed authority.

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

Double free in the Android kernel allows local users with System execution privileges to elevate privileges without user interaction. The gasket_free_coherent_memory_all function in gasket_page_table.c releases coherent-memory bookkeeping twice, corrupting kernel memory. Exploitation requires local code already running with System execution privileges and grants higher kernel-backed authority.

The record

CVE
CVE-2021-39725
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-415, 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?

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  1. Affected versionversion=Android kernel

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Google Cloud · Androidversion=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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
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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