CVE-2023-40399

Kernel-memory disclosure via undisclosed memory-handling flaw

Published Sep 26, 2023 · Updated Nov 4, 2025

Memory-handling flaw in Apple Neural Engine across iOS, iPadOS, tvOS, watchOS, and macOS allows local users to disclose kernel memory through an app. Apple has not disclosed the faulty operation or the untrusted input involved beyond stating that improved memory handling resolved the issue. Exploitation requires execution of an app on a device with Apple Neural Engine support, and the reported consequence is kernel-memory disclosure without integrity or availability impact.

CVSS severity5.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory-handling flaw in Apple Neural Engine across iOS, iPadOS, tvOS, watchOS, and macOS allows local users to disclose kernel memory through an app. Apple has not disclosed the faulty operation or the untrusted input involved beyond stating that improved memory handling resolved the issue. Exploitation requires execution of an app on a device with Apple Neural Engine support, and the reported consequence is kernel-memory disclosure without integrity or availability impact.

The record

CVE
CVE-2023-40399
Published
Sep 26, 2023
Updated
Nov 4, 2025
Vendor
Apple
Product
iOS and iPadOS
Classifications
Unavailable
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 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=unspecified <17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <17
Apple · tvOSversion=unspecified <17
Apple · macOSversion=unspecified <14
Apple · watchOSversion=unspecified <10

Published CVSS scores

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

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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