CVE-2024-40857Network attack vector

Universal cross-site scripting via persistent WebArchive state

Published Sep 16, 2024 · Updated Apr 2, 2026

Universal cross-site scripting in WebKit on affected Apple platforms allows remote attackers to execute script across normally isolated origins. The page-loading path opens WebArchive content with a persistent website data store instead of isolating it in a non-persistent store. Exploitation requires processing a malicious WebArchive or related web content; successful script execution can read or modify content across site origins.

CVSS severity6.1
Medium
EPSS probability0.55%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Universal cross-site scripting in WebKit on affected Apple platforms allows remote attackers to execute script across normally isolated origins. The page-loading path opens WebArchive content with a persistent website data store instead of isolating it in a non-persistent store. Exploitation requires processing a malicious WebArchive or related web content; successful script execution can read or modify content across site origins.

The record

CVE
CVE-2024-40857
Published
Sep 16, 2024
Updated
Apr 2, 2026
Vendor
Apple
Product
iOS and iPadOS
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record 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=0 <18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOS and iPadOSversion=0 <18
Apple · visionOSversion=0 <2
Apple · Safariversion=0 <18
Apple · tvOSversion=0 <18
Apple · macOSversion=0 <15
Apple · watchOSversion=0 <11

Published CVSS scores

6.1NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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