CVE intelligence and bounded remediation

CVE-2023-38500 — Typo3 Html Sanitizer security vulnerability

Medium CVSS 6.1

TYPO3 HTML Sanitizer is an HTML sanitizer, written in PHP, aiming to provide cross-site-scripting-safe markup based on explicitly allowed tags, attributes and values. Starting in version 1.0.0 and prior to versions 1.5.1 and 2.1.2, 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. Versions 1.5.1 and 2.1.2 fix the problem.

Severity
Medium
CVSS
6.1 (3.1)
Published
2023-07-25
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-79

Affected products

  • typo3 / html_sanitizer

Showing 1 representative product identities from 2 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cross-site scripting and unsafe browser output

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Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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