Authenticated open redirect via PHP-WHATWG hostname discrepancy
Published Jul 1, 2026 · Updated Jul 1, 2026
URL validation bypass in Wikimedia Foundation UrlShortener allows remote authenticated users to create short links to disallowed hosts. UrlShortenerUtils.php validates a PHP-parsed hostname without rejecting backslashes, while browsers apply WHATWG parsing and resolve a different host. A user with URL-shortening permission can turn a trusted short-link domain into a redirect to an attacker-selected external site.
Summary
What happened
URL validation bypass in Wikimedia Foundation UrlShortener allows remote authenticated users to create short links to disallowed hosts. UrlShortenerUtils.php validates a PHP-parsed hostname without rejecting backslashes, while browsers apply WHATWG parsing and resolve a different host. A user with URL-shortening permission can turn a trusted short-link domain into a redirect to an attacker-selected external site.
The record
- CVE
- CVE-2026-13706
- Published
- Jul 1, 2026
- Updated
- Jul 1, 2026
- Vendor
- Wikimedia Foundation
- Product
- UrlShortener
- Classifications
- CWE-20, T1566.002
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 1, 2026CVE publishedPublication date reported by the CVE source.
- Jul 1, 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?
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- Affected versionversion=* <=1.46.0, 1.45.4, 1.44.6, 1.43.9
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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Your stack
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