CVE-2023-38500

CVSS: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C (4.4)

Problem

Due to an encoding issue in the serialization layer, malicious markup nested in a noscript element was not encoded correctly. noscript is disabled in the default configuration, but might have been enabled in custom scenarios. This allows bypassing the cross-site scripting mechanism of typo3/html-sanitizer.

Credits

Thanks to David Klein and Yaniv Nizry who reported this issue, and to TYPO3 security team members Oliver Hader and Benjamin Franzke who fixed the issue.

References

• TYPO3-CORE-SA-2023-002

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-2023-38500 has a CVSS score of 4.7 (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 (1.5.1, 2.1.2); upgrading removes the vulnerable code path.

Kodem intelligence

Update to typo3/html-sanitizer versions 1.5.1 or 2.1.2 that fix the problem described.

1. What is CVE-2023-38500? CVE-2023-38500 is a medium-severity cross-site scripting (XSS) vulnerability in typo3/html-sanitizer (composer), affecting versions >= 1.0.0, < 1.5.1. It is fixed in 1.5.1, 2.1.2. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2023-38500? CVE-2023-38500 has a CVSS score of 4.7 (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 versions of typo3/html-sanitizer are affected by CVE-2023-38500? typo3/html-sanitizer (composer) versions >= 1.0.0, < 1.5.1 is affected.
4. Is there a fix for CVE-2023-38500? Yes. CVE-2023-38500 is fixed in 1.5.1, 2.1.2. Upgrade to this version or later.
5. Is CVE-2023-38500 exploitable, and should I be worried? Whether CVE-2023-38500 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-2023-38500 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-2023-38500?
   • Upgrade typo3/html-sanitizer to 1.5.1 or later
   • Upgrade typo3/html-sanitizer to 2.1.2 or later

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