CVE-2026-46721: Broken Access Control in extension "Frontend User Registration" (sf_register)

Vulnerability summary

CVE-2026-46721 is a medium (CVSS 6.9) vulnerability in typo3 extension "frontend user registration". EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 30.1% of scored vulnerabilities.

Timeline

1. 19-05-2026
   PublishedVulnerability first disclosed.
2. 19-05-2026
   Last modifiedVulnerability information updated.

Description

The create and edit flows do not restrict which user properties may be submitted and do not enforce access control on the frontend user group assignment. As a result, an attacker can assign an arbitrary frontend user group to a newly registered or edited account, gaining unauthorized access to content and functionality restricted to privileged frontend user groups.

• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
• CWE-915Improperly Controlled Modification of Dynamically-Determined Object AttributesThe product receives input from an upstream component that specifies multiple attributes, properties, or fields that are to be initialized or updated in an object, but it does not properly control which attributes can be modified.