Joomla! Core - [20260915] - Core - XSS filter bypass in InputFilter via HTML5 entity decode mismatch in Joomla 1.5.0-5.4.8, 6.0.0-6.1.3

Why this deserves its current priority

CVSS is 7.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Affected scope and exposure questions

The current feed maps Joomla! Project/Joomla! CMS (generic), Joomla! Project/Joomla! Framework Filter package (generic). Check affected ranges and fixed versions before updating.

Recommended response

1. 1Check inventory. Check lockfiles and deployed manifests for Joomla! Project/Joomla! CMS, Joomla! Project/Joomla! Framework Filter package.
2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

1. Published upstream

   Sep 29, 2026

   Evidence: source:cvelist:source_dates:source-dates:record

2. Source modified

   Sep 29, 2026

   Evidence: source:cvelist:source_dates:source-dates:record

3. First seen by HOL

   Sep 29, 2026

Sources and claim methodology

• Source referencedeveloper.joomla.org
• Source referencejoomla.org

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