CVE-2026-20643Network attack vector

Same-origin-policy bypass via incomplete Navigation API checks

Published Mar 17, 2026 · Updated Mar 17, 2026

Origin validation error in WebKit on iOS, iPadOS, and macOS allows remote attackers to bypass Same Origin Policy via crafted web content. The documentCanHaveURLRewritten function accepts HTTP(S) targets without first requiring the document and target ports and other origin components to match. Loading attacker-controlled content is required; successful exploitation permits a page to intercept cross-port navigation across an origin boundary.

CVSS severity5.4
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in WebKit on iOS, iPadOS, and macOS allows remote attackers to bypass Same Origin Policy via crafted web content. The documentCanHaveURLRewritten function accepts HTTP(S) targets without first requiring the document and target ports and other origin components to match. Loading attacker-controlled content is required; successful exploitation permits a page to intercept cross-port navigation across an origin boundary.

The record

CVE
CVE-2026-20643
Published
Mar 17, 2026
Updated
Mar 17, 2026
Vendor
Apple
Product
iOS
Classifications
CWE-20, CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 17, 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=unspecified <26.3.1 (a)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apple · iOSversion=unspecified <26.3.1 (a)
Apple · macOSversion=unspecified <26.3.1 (a); version=unspecified <26.3.2 (a)
Apple · iPadOSversion=unspecified <26.3.1 (a)

Published CVSS scores

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
CWE-346Origin Validation Error
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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