Improper Encoding or Escaping of Output Affecting htmlsanitizer package, versions [,9.0.892)[9.1.878-beta,9.1.893-beta)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published4 Feb 2026
- disclosed3 Feb 2026
- creditnsysean
Introduced: 3 Feb 2026
NewCVE-2026-25543 (opens in a new tab)How to fix?
Upgrade HtmlSanitizer to version 9.0.892, 9.1.893-beta or higher.
Overview
HtmlSanitizer is a Cleans HTML from constructs that can be used for cross site scripting (XSS).
Affected versions of this package are vulnerable to Improper Encoding or Escaping of Output in the template tag handling. An attacker can inject and execute arbitrary scripts by crafting HTML content that leverages unsanitized template tags, potentially using deep DOM nesting or the shadowrootmode attribute to bypass sanitization.
Note:
This is only exploitable if the template tag is explicitly allowed in the sanitizer configuration or if the shadowrootmode attribute is permitted.
Workaround
This vulnerability can be mitigated by disallowing the template tag, which is the default configuration.