CVE-2023-21400Public exploit

Kernel privilege escalation via io_uring double free

Published Jul 12, 2023 · Updated Feb 13, 2025

Memory corruption in Android kernel io_uring allows local users with System execution privileges to escalate privileges without interaction. Improper locking in deferred request handling can free an io_defer_entry object twice, corrupting the kernel heap. Exploitation requires code execution outside an app Zygote sandbox, such as in a system component, and grants kernel-level privileges.

CVSS severity6.7
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Android kernel io_uring allows local users with System execution privileges to escalate privileges without interaction. Improper locking in deferred request handling can free an io_defer_entry object twice, corrupting the kernel heap. Exploitation requires code execution outside an app Zygote sandbox, such as in a system component, and grants kernel-level privileges.

The record

CVE
CVE-2023-21400
Published
Jul 12, 2023
Updated
Feb 13, 2025
Vendor
Google
Product
Android
Classifications
CWE-667, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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 privilegesadmin

What is affected?

Google · Androidversion=Android kernel

Published CVSS scores

6.7NIST National Vulnerability DatabaseCVSS: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

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 exploitPublished

Weakness, pattern, technique

CWE-667Improper Locking
T1068Exploitation for Privilege Escalation

Public exploit references

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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