CVE-2021-39801

Local privilege escalation via ion_ioctl use after free

Published Apr 12, 2022 · Updated Aug 4, 2024

Use-after-free in ion_ioctl of Google Cloud Android kernel allows local users to gain privileges through crafted ION ioctl calls. The function releases or reuses ION buffer state under improper locking, permitting a concurrent operation to access freed kernel memory. Exploitation requires a local application with low privileges and no user interaction; successful exploitation can compromise kernel confidentiality, integrity, and availability.

CVSS severity7.8
High
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 ion_ioctl of Google Cloud Android kernel allows local users to gain privileges through crafted ION ioctl calls. The function releases or reuses ION buffer state under improper locking, permitting a concurrent operation to access freed kernel memory. Exploitation requires a local application with low privileges and no user interaction; successful exploitation can compromise kernel confidentiality, integrity, and availability.

The record

CVE
CVE-2021-39801
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-667, CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 12, 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 privilegesauthenticated

What is affected?

Google Cloud · Androidversion=Android kernel

Published CVSS scores

7.8NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.2NVDAV:L/AC:L/Au:N/C:C/I:C/A:C

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-667Improper Locking
CWE-416Use After Free
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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