---
title: "TYPO3-CORE-SA-2017-002: Authentication Bypass in TYPO3 Frontend"
url: "https://news.typo3.com/security/advisory/typo3-core-sa-2017-002"
description: It has been discovered, that TYPO3 CMS is vulnerable to Authentication Bypass.
image: "https://news.typo3.com/_assets/d1e01514e4c4a5b3147940fa2ec50682/Images/og-image-news.jpg"
date: 2026-06-11
modified: 2026-06-11
categories:
  - "Product Updates & Roadmap"
  - TYPO3 CMS
---

# TYPO3-CORE-SA-2017-002: Authentication Bypass in TYPO3 Frontend

- [Product Updates & Roadmap](https://news.typo3.com/article/category/product-updates-roadmap)
- Security / [TYPO3 CMS](https://news.typo3.com/article/category/security/typo3-cms)

TYPO3-CORE-SA-2017-002: Authentication Bypass in TYPO3 Frontend
===============================================================

28 February 2017

![A laptop screen displaying a list of security advisories](https://news.typo3.com/typo3temp/assets/_processed_/d/c/csm_security_blog_default_77f8e86036.webp)

It has been discovered, that TYPO3 CMS is vulnerable to Authentication Bypass.

- ![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/bbf959d8e683550c90ae922aff9145d8.jpeg)[Marcus Krause](https://news.typo3.com/article/author/marcus-krause)

**Component Type:** TYPO3 CMS

**Release Date:** February 28, 2017

Vulnerable subcomponent: Frontend
---------------------------------

**Vulnerability Type:** Authentication Bypass

**Affected Versions:** Versions 8.2.0 to 8.6.0

**Severity:** Medium

**Suggested CVSS v2.0:** [AV:N/AC:L/Au:S/C:P/I:P/A:N/E:P/RL:O/RC:C](http://jvnrss.ise.chuo-u.ac.jp/jtg/cvss/cvss2.cgi?vector=%28AV:N/AC:L/Au:S/C:P/I:P/A:N/E:P/RL:O/RC:C%29&g=2&lang=en)

**CVE:**  not assigned yet

**Problem Description:** Due to late TCA initialization the authentication service fails to restrict frontend user according to the validation rules. Therefore it is possible to authenticate restricted (e.g. disabled) frontend users.

**Solution:** Update to TYPO3 version 8.6.1 that fixes the problem described.

**Credits:** Thanks to Thomas Dahlke who discovered and reported the issue.

**General Advice:** Follow the recommendations that are given in the [TYPO3 Security Guide](http://docs.typo3.org/typo3cms/SecurityGuide/ "Opens external link in new window"). Please subscribe to the [typo3-announce](http://lists.typo3.org/cgi-bin/mailman/listinfo/typo3-announce) mailing list.

**General Note:** All security related code changes are tagged so that you can easily look them up on our [review system](https://review.typo3.org/#/q/status:merged+project:Packages/TYPO3.CMS+topic:security,n,z).

![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/b5c88386e5b1d8fca79d0652427922d2.jpeg)

About the Author

[Marcus Krause](https://news.typo3.com/article/author/marcus-krause)

[More posts by this author](https://news.typo3.com/article/author/marcus-krause)