CVE-2025-43421Network attack vector

Process crash via unsafe array allocation sinking

Published Nov 4, 2025 · Updated Nov 4, 2025

WebKit flaws in Apple operating systems and Safari before 26.1 allow remote attackers to crash a web-content process with crafted content. WebKit's array allocation sinking optimization performs unsafe transformations on crafted JavaScript arrays; Apple has not disclosed the individual faulting operations. A victim must process attacker-controlled web content, and the documented consequence is a process crash rather than device shutdown or code execution.

CVSS severity4.3
Medium
EPSS probability0.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

WebKit flaws in Apple operating systems and Safari before 26.1 allow remote attackers to crash a web-content process with crafted content. WebKit's array allocation sinking optimization performs unsafe transformations on crafted JavaScript arrays; Apple has not disclosed the individual faulting operations. A victim must process attacker-controlled web content, and the documented consequence is a process crash rather than device shutdown or code execution.

The record

CVE
CVE-2025-43421
Published
Nov 4, 2025
Updated
Nov 4, 2025
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-125, CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 4, 2025CVE 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 <26.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=unspecified <26.1
Apple · visionOSversion=unspecified <26.1
Apple · Safariversion=unspecified <26.1

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

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-125Out-of-bounds Read
CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

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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