Unauthenticated account creation via unchecked WebAuthn preparation
Published Feb 27, 2026 · Updated Feb 27, 2026
Missing authorization in phpMyFAQ before 4.0.18 allows remote attackers to create active accounts through the WebAuthn prepare endpoint. WebAuthnController::prepare accepts an arbitrary username and creates and activates the user without checking registration or WebAuthn settings or validating a CSRF token. The route is enabled by default regardless of configuration, permitting account proliferation and username squatting without authentication.
Summary
What happened
Missing authorization in phpMyFAQ before 4.0.18 allows remote attackers to create active accounts through the WebAuthn prepare endpoint. WebAuthnController::prepare accepts an arbitrary username and creates and activates the user without checking registration or WebAuthn settings or validating a CSRF token. The route is enabled by default regardless of configuration, permitting account proliferation and username squatting without authentication.
The record
- CVE
- CVE-2026-27836
- Published
- Feb 27, 2026
- Updated
- Feb 27, 2026
- Vendor
- Thorsten Rinne
- Product
- phpMyFAQ
- Classifications
- CWE-862, T1136
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 27, 2026CVE publishedPublication date reported by the CVE source.
- Feb 27, 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=< 4.0.18
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- WebAuthn prepare endpoint curl proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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