CVE-2021-39792

Local kernel-memory disclosure via stale USB request

Published Mar 16, 2022 · Updated Aug 4, 2024

Information disclosure in the Android kernel allows local users with System privileges to read out-of-bounds kernel memory through USB. The USB accessory driver's cleanup paths free receive requests without clearing their array entries, so acc_read can reuse a stale request while usb_gadget_giveback_request completes it. Exploitation requires System-level execution on an affected device and a race against USB request teardown, but no user interaction is required.

CVSS severity4.1
Medium
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in the Android kernel allows local users with System privileges to read out-of-bounds kernel memory through USB. The USB accessory driver's cleanup paths free receive requests without clearing their array entries, so acc_read can reuse a stale request while usb_gadget_giveback_request completes it. Exploitation requires System-level execution on an affected device and a race against USB request teardown, but no user interaction is required.

The record

CVE
CVE-2021-39792
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-362, T1005
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

4.1NIST NVDCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N
1.9NIST NVDAV:L/AC:M/Au:N/C:P/I:N/A:N

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 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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1005Data from Local System

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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