CVE-2021-32768

Meta

• CVSS: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC (5.7)

Problem

Failing to properly parse, sanitize and encode malicious rich-text content, the content rendering process in the website frontend is vulnerable to cross-site scripting. Corresponding rendering instructions via TypoScript functionality HTMLparser do not consider all potentially malicious HTML tag & attribute combinations per default.

In addition, the lack of comprehensive default node configuration for rich-text fields in the backend user interface fosters this malfunction.

In default scenarios, a valid backend user account is needed to exploit this vulnerability. In case custom plugins used in the website frontend accept and reflect rich-text content submitted by users, no authentication is required.

Credits

Thanks to Benjamin Stiber, Gert-Jan Jansma, Gábor Ács-Kurucz, Alexander Kellner, Richie Lee, Nina Rösch who reported this issue, and to TYPO3 security team member Oliver Hader, as well as TYPO3 contributor Susanne Moog who fixed the issue.

References

• TYPO3-CORE-SA-2021-013

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2021-32768 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (7.6.53, 8.7.42, 10.4.19, 11.3.2, 9.5.29); upgrading removes the vulnerable code path.

Kodem intelligence

Update to TYPO3 versions 7.6.53 ELTS, 8.7.42 ELTS, 9.5.29, 10.4.19, 11.3.2 that fix the problem described above.

Custom package typo3/html-sanitizer - based on allow-lists only - takes care of sanitizing potentially malicious markup. The default behavior is based on safe and commonly used markup - however, this can be extended or restricted further in case it is necessary for individual scenarios.

During the frontend rendering process, sanitization is applied to the default TypoScript path lib.parseFunc, which is implicitly used by the Fluid view-helper instruction f:format.html. Rich-text data persisted using the backend user interface is sanitized as well. Implementation details are explained in corresponding ChangeLog documentation.

1. What is CVE-2021-32768? CVE-2021-32768 is a medium-severity cross-site scripting (XSS) vulnerability in typo3/cms-core (composer), affecting versions >= 7.0.0, < 7.6.53. It is fixed in 7.6.53, 8.7.42, 10.4.19, 11.3.2, 9.5.29. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2021-32768? CVE-2021-32768 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which packages are affected by CVE-2021-32768?
   • typo3/cms-core (composer) (versions >= 7.0.0, < 7.6.53)
   • typo3/cms (composer) (versions >= 10.0.0, < 10.4.19)
4. Is there a fix for CVE-2021-32768? Yes. CVE-2021-32768 is fixed in 7.6.53, 8.7.42, 10.4.19, 11.3.2, 9.5.29. Upgrade to this version or later.
5. Is CVE-2021-32768 exploitable, and should I be worried? Whether CVE-2021-32768 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2021-32768 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2021-32768?
   • Upgrade typo3/cms-core to 7.6.53 or later
   • Upgrade typo3/cms-core to 8.7.42 or later
   • Upgrade typo3/cms-core to 10.4.19 or later
   • Upgrade typo3/cms-core to 11.3.2 or later
   • Upgrade typo3/cms-core to 9.5.29 or later
   • Upgrade typo3/cms to 10.4.19 or later
   • Upgrade typo3/cms to 11.3.2 or later
   • Upgrade typo3/cms to 9.5.29 or later
   • Upgrade typo3/cms to 8.7.42 or later
   • Upgrade typo3/cms to 7.6.53 or later