--- title: "TYPO3-EXT-SA-2021-007: Cross-Site Scripting in extension \"Bootstrap Package\" (bootstrap_package)" url: "https://news.typo3.com/security/advisory/typo3-ext-sa-2021-007" description: "It has been discovered that the extension \"Bootstrap Package\" (bootstrap_package) is susceptible to Cross-Site Scripting." 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-2021-007: Cross-Site Scripting in extension "Bootstrap Package" (bootstrap_package) - [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-2021-007: Cross-Site Scripting in extension "Bootstrap Package" (bootstrap\_package) ================================================================================================= 27 April 2021 ![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 "Bootstrap Package" (bootstrap\_package) is susceptible to Cross-Site Scripting. - ![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/e4eaa13e33dd086a9c06f2570cb34609.jpeg)[Torben Hansen](https://news.typo3.com/article/author/torben-hansen) - Release Date: April 27, 2021 - Component Type: Third party extension. This extension is not a part of the TYPO3 default installation. - Component: "Bootstrap Package" (bootstrap\_package) - Vulnerability Type: Cross-Site Scripting - Affected Versions: 11.0.0 - 11.0.2, 10.0.0 - 10.0.9, 9.0.0-9.0.3, 9.1.0-9.1.2, 8.0.0 - 8.0.7, 7.1.1 and below - Severity: Medium - Suggested CVSS: [CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C](https://nvd.nist.gov/vuln-metrics/cvss/v3-calculator?vector=AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C&version=3.1) - References: [CVE-2021-21365](https://nvd.nist.gov/vuln/detail/CVE-2021-21365) ### Problem Description The extension fails to properly encode user input for output in HTML context. The following templates are affected by the vulnerability: - Resources/Private/Partials/ContentElements/Carousel/Item/CallToAction.html - Resources/Private/Partials/ContentElements/Carousel/Item/Header.html - Resources/Private/Partials/ContentElements/Carousel/Item/Text.html - Resources/Private/Partials/ContentElements/Carousel/Item/TextAndImage.html - Resources/Private/Partials/ContentElements/Header/SubHeader.html Users of the extension, who have overwritten the affected templates must manually apply required changes as shown below: **Vulnerable:** {userInput} **Not vulnerable:** {userInput} ### Solution Updated versions 7.1.2, 8.0.8, 9.0.4, 9.1.3, 10.0.10, 11.0.3 are available from the TYPO3 extension manager, Packagist and at Users of the extension are advised to update the extension as soon as possible. ### Credits Thanks to TYPO3 Security Team Member Oliver Hader who reported and fixed the issue. ### 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)