--- title: "TYPO3-EXT-SA-2014-013: Denial of Service vulnerability in extension Calendar Base (cal)" url: "https://news.typo3.com/security/advisory/typo3-ext-sa-2014-013" description: "It has been discovered that the extension \"Calendar Base\" (cal) 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: - TYPO3 Extensions --- # TYPO3-EXT-SA-2014-013: Denial of Service vulnerability in extension Calendar Base (cal) - Security / [TYPO3 Extensions](https://news.typo3.com/article/category/security/typo3-extensions) TYPO3-EXT-SA-2014-013: Denial of Service vulnerability in extension Calendar Base (cal) ======================================================================================= 17 October 2014 ![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 "Calendar Base" (cal) is susceptible to Denial of Service. - ![](https://news.typo3.com/typo3temp/assets/t3g/blog/gravatar/bbf959d8e683550c90ae922aff9145d8.jpeg)[Marcus Krause](https://news.typo3.com/article/author/marcus-krause) **Release Date:** October 17, 2014 **Bulletin Update:** October 18, 2014 (added CVE) **Component Type:** Third party extension. This extension is not a part of the TYPO3 default installation. **Affected Versions:** all versions of 0.x.x, 1.0.x, 1.1.x, 1.2.x, 1.3.x, 1.4.x; 1.5.8 and below of 1.5.x; 1.6.0 **Vulnerability Type:** Denial of Service **Severity:** Medium **Suggested CVSS v2.0:** AV:N/AC:M/Au:N/C:N/I:N/A:C/E:POC/RL:OF/RC:C **CVE:** CVE-2014-8325 **Problem Description:** User input is passed to PHP's PCRE library without validating it beforehand. Depending on user input this may consume a tremendous amount of system resources. **Solution:** Updated versions 1.5.9 (for TYPO3 CMS 4.5.5 - 6.0.99) and 1.6.1 (for TYPO3 CMS 6.1.0 - 6.2.99) are available from the TYPO3 extension manager and at [http://typo3.org/extensions/repository/download/cal/1.6.1/t3x/](http://typo3.org/extensions/repository/download/cal/1.6.1/t3x/ "Opens external link in new window") and [http://typo3.org/extensions/repository/download/cal/1.5.9/t3x/](http://typo3.org/extensions/repository/download/cal/1.5.9/t3x/ "Opens external link in new window"). Users of the extension are advised to update the extension as soon as possible. **Credits:** Credits go to Daniel Hahler and Bernd Schuhmacher 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/ "Initiates file download"). Please subscribe to the [typo3-announce mailing list](http://lists.typo3.org/cgi-bin/mailman/listinfo/typo3-announce "Opens external link in new window") to receive future Security Bulletins via E-mail. ![](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)