Unauthenticated open redirects via unanchored domain allowlist
Published Jul 1, 2026 · Updated Jul 1, 2026
Open redirect in Wikimedia Foundation UrlShortener before 1.43.9, 1.44.6, and 1.45.4 allows remote attackers to create links to untrusted sites. The default getAllowedDomainsRegex() logic builds an unanchored allowlist expression from the server value, so lookalike hosts such as example.org.imposter.invalid pass validation. No authentication is required; accepted destinations produce short URLs that redirect visitors to attacker-controlled sites, enabling phishing or content spoofing.
Summary
What happened
Open redirect in Wikimedia Foundation UrlShortener before 1.43.9, 1.44.6, and 1.45.4 allows remote attackers to create links to untrusted sites. The default getAllowedDomainsRegex() logic builds an unanchored allowlist expression from the server value, so lookalike hosts such as example.org.imposter.invalid pass validation. No authentication is required; accepted destinations produce short URLs that redirect visitors to attacker-controlled sites, enabling phishing or content spoofing.
The record
- CVE
- CVE-2026-58520
- Published
- Jul 1, 2026
- Updated
- Jul 1, 2026
- Vendor
- Wikimedia Foundation
- Product
- UrlShortener
- Classifications
- CWE-601, T1566
- Attack vector
- network
- Privileges
- unauthenticated
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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=* <1.43.9, 1.44.6, 1.45.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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