CVE-2021-1825Public exploitNetwork attack vector

Cross-site scripting via unencoded URL fragments

Published Sep 8, 2021 · Updated Aug 3, 2024

Cross-site scripting in WebKit across affected Apple products allows remote attackers to execute script via crafted web content. WebKit fails to percent-encode angle brackets and double quotes in URL fragments before exposing them through location properties. Exploitation requires a page that inserts the fragment into HTML without adequate sanitization and either disables the XSS auditor or permits a bypass.

CVSS severity6.1
Medium
EPSS probability1.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in WebKit across affected Apple products allows remote attackers to execute script via crafted web content. WebKit fails to percent-encode angle brackets and double quotes in URL fragments before exposing them through location properties. Exploitation requires a page that inserts the fragment into HTML without adequate sanitization and either disables the XSS auditor or permits a bypass.

The record

CVE
CVE-2021-1825
Published
Sep 8, 2021
Updated
Aug 3, 2024
Vendor
Apple
Product
iTunes for Windows
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <12.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iTunes for Windowsversion=unspecified <12.11
Apple · iOS and iPadOSversion=unspecified <14.5
Apple · Safariversion=unspecified <14.1
Apple · iCloud for Windowsversion=unspecified <12.3
Apple · tvOSversion=unspecified <14.5
Apple · macOSversion=unspecified <11.3
Apple · watchOSversion=unspecified <7.4

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS: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 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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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