VDB-348194 · CVE-2026-27836 · GHSA-w22q-m2fm-x9f4

thorsten phpmyfaq up to 4.0.17 WebAuthn Prepare Endpoint /api/webauthn/prepare authorization

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.3	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic was found in thorsten phpmyfaq up to 4.0.17. Affected by this vulnerability is an unknown functionality of the file /api/webauthn/prepare of the component WebAuthn Prepare Endpoint. Such manipulation leads to authorization. This vulnerability is traded as CVE-2026-27836. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in thorsten phpmyfaq up to 4.0.17. Affected by this issue is an unknown function of the file /api/webauthn/prepare of the component WebAuthn Prepare Endpoint. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Impacted is integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-27836 since 02/24/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit.

Upgrading to version 4.0.18 eliminates this vulnerability. Applying the patch f2ab673f0668753cd0f7c7c8bc7fd2304dcf5cb1 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-9059). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Content Management System

Vendor

thorsten

Name

phpmyfaq

Version

License

open-source

Website

Product: https://github.com/thorsten/phpMyFAQ/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authorization
CWE: CWE-862 / CWE-863 / CWE-285
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: phpmyfaq 4.0.18
Patch: f2ab673f0668753cd0f7c7c8bc7fd2304dcf5cb1

Timelineinfo

02/24/2026 CVE reserved
02/27/2026 +3 days Advisory disclosed
02/27/2026 +0 days VulDB entry created
03/05/2026 +6 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-w22q-m2fm-x9f4
Status: Confirmed

CVE: CVE-2026-27836 (🔒)
GCVE (CVE): GCVE-0-2026-27836
GCVE (VulDB): GCVE-100-348194
EUVD: 🔒

Entryinfo

Created: 02/27/2026 22:12
Updated: 03/05/2026 19:24
Changes: 02/27/2026 22:12 (68), 02/28/2026 23:07 (1), 03/05/2026 19:24 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.