CVE-2023-39434Network attack vector

Arbitrary code execution via WebKit use-after-free

Published Sep 26, 2023 · Updated May 2, 2025

Use-after-free in WebKit before iOS 17, watchOS 10, and macOS 14 allows remote attackers to execute code through web content. WebKit accesses an object after its memory has been freed while processing crafted content; Apple has not disclosed the affected object or code path. Successful exploitation runs attacker-controlled code after a user or application processes malicious web content.

CVSS severity8.8
High
EPSS probability1.51%
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 WebKit before iOS 17, watchOS 10, and macOS 14 allows remote attackers to execute code through web content. WebKit accesses an object after its memory has been freed while processing crafted content; Apple has not disclosed the affected object or code path. Successful exploitation runs attacker-controlled code after a user or application processes malicious web content.

The record

CVE
CVE-2023-39434
Published
Sep 26, 2023
Updated
May 2, 2025
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 26, 2023CVE publishedPublication date reported by the CVE source.
  2. May 2, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

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

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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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