CVE-2021-39638

Local privilege escalation via freed periodic-I/O memory

Published Dec 15, 2021 · Updated Aug 4, 2024

Use-after-free in the Android kernel camera component allows local users with System execution privileges to escalate privileges. The periodic_io_work_func routine in lwis_periodic_io.c accesses freed memory and performs an out-of-bounds write during periodic I/O processing. Exploitation requires local System execution privileges and no user interaction; successful exploitation corrupts kernel memory to elevate privileges.

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

Use-after-free in the Android kernel camera component allows local users with System execution privileges to escalate privileges. The periodic_io_work_func routine in lwis_periodic_io.c accesses freed memory and performs an out-of-bounds write during periodic I/O processing. Exploitation requires local System execution privileges and no user interaction; successful exploitation corrupts kernel memory to elevate privileges.

The record

CVE
CVE-2021-39638
Published
Dec 15, 2021
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-416, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 15, 2021CVE 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

4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
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

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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-416Use After Free
T1068Exploitation 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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