--- title: "TYPO3-EXT-SA-2020-020: Denial of Service in extension \"Authenticator\" (defbu_authenticator)" url: "https://news.typo3.com/security/advisory/typo3-ext-sa-2020-020" description: "It has been discovered that the extension \"Authenticator\" (defbu_authenticator) is susceptible to Denial of Service." image: "https://news.typo3.com/_assets/d1e01514e4c4a5b3147940fa2ec50682/Images/og-image-news.jpg" date: 2026-06-11 modified: 2026-06-11 categories: - "Developer & Technology" - TYPO3 Extensions --- # TYPO3-EXT-SA-2020-020: Denial of Service in extension "Authenticator" (defbu_authenticator) - [Developer & Technology](https://news.typo3.com/article/category/developer-technology) - Security / [TYPO3 Extensions](https://news.typo3.com/article/category/security/typo3-extensions) TYPO3-EXT-SA-2020-020: Denial of Service in extension "Authenticator" (defbu\_authenticator) ============================================================================================ 17 November 2020 ![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 the extension "Authenticator" (defbu\_authenticator) is susceptible to Denial of Service. - ![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/e4eaa13e33dd086a9c06f2570cb34609.jpeg)[Torben Hansen](https://news.typo3.com/article/author/torben-hansen) - Release Date: November 17, 2020 - Component Type: Third party extension. This extension is not a part of the TYPO3 default installation. - Component: Authenticator (defbu\_authenticator) - Vulnerability Type: Denial of Service - Affected Versions: 1.0.2 and below - Severity: High - Suggested CVSS v3.1: [AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C](https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C&version=3.1) - References: N/A ### Problem Description The extension bundles demo files of a 3rd party QR Code generator allowing a remote user to create QR Codes saved as PNG files on the webserver. This  can result in Denial of Service, since the webspace can be filled up with a large amount of PNG files. ### Solution An updated version 1.0.3  is available from the TYPO3 extension manager and at . Users of the extension are advised to update the extension as soon as possible. ### Credits Thanks to TYPO3 security team member Georg Ringer for reporting the issue and to Frank Buijze for providing an updated version of the extension. ### General Advice Follow the recommendations that are given in the [TYPO3 Security Guide](https://docs.typo3.org/typo3cms/CoreApiReference/Security/Index.html#security-guidelines). Please subscribe to the [typo3-announce](http://lists.typo3.org/cgi-bin/mailman/listinfo/typo3-announce) mailing list. ![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/7cf52722a5b7183b29d378a2284bd103.jpeg) About the Author [Torben Hansen](https://news.typo3.com/article/author/torben-hansen) Open Source Enthusiast & TYPO3 Expert I’m a passionate open-source advocate and dedicated TYPO3 expert. As a freelancer, I offer professional TYPO3 services to clients while actively contributing to the TYPO3 ecosystem. I have developed several public TYPO3 extensions and serve as the Co-Lead of the TYPO3 Security Team, helping to enhance the platform’s security and functionality. For many years, I have been blogging about TYPO3, sharing insights and expertise with the community. [More posts by this author](https://news.typo3.com/article/author/torben-hansen)