Vulnerability · Published Feb 27, 2026 · Assigned by GitHub_M

CVE-2026-27836phpMyFAQ Allows Unauthenticated Account Creation via WebAuthn Prepare Endpoint

High 7.5

In plain English

A high-severity missing authorization in phpMyFAQ from thorsten. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.5%top 60.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

phpMyFAQ is an open source FAQ web application. Prior to version 4.0.18, the WebAuthn prepare endpoint (`/api/webauthn/prepare`) creates new active user accounts without any authentication, CSRF protection, captcha, or configuration checks. This allows unauthenticated attackers to create unlimited user accounts even when registration is disabled. Version 4.0.18 fixes the issue.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	thorsten/phpmyfaq	4.0.18	GHSA-w22q-m2fm-x9f4

Affected products (as reported)

Vendor	Product	Versions
thorsten	phpMyFAQ	< 4.0.18

Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

References

https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-w22q-m2fm-x9f4 x_refsource_CONFIRM
https://github.com/thorsten/phpMyFAQ/commit/f2ab673f0668753cd0f7c7c8bc7fd2304dcf5cb1 x_refsource_MISC