CVE-2021-39800

Local kernel-data disclosure via premature handle release

Published Apr 12, 2022 · Updated Aug 4, 2024

Use-after-free in the ION kernel component in Google Cloud Android kernel allows local users to disclose kernel heap data through ioctl calls. In ion_ioctl, pass_to_user drops the live ION handle reference before its final use, allowing the client to free the referenced object prematurely. Exploitation requires local low-privileged access but no user interaction, and the reported consequence is limited to kernel-data disclosure.

CVSS severity5.5
Medium
EPSS probability0.14%
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 ION kernel component in Google Cloud Android kernel allows local users to disclose kernel heap data through ioctl calls. In ion_ioctl, pass_to_user drops the live ION handle reference before its final use, allowing the client to free the referenced object prematurely. Exploitation requires local low-privileged access but no user interaction, and the reported consequence is limited to kernel-data disclosure.

The record

CVE
CVE-2021-39800
Published
Apr 12, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-416
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?

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  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

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

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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