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Fix: Harden FreeMarker against SSTI #705

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angelozerr merged 2 commits into from
Nov 15, 2025
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Fix: Harden FreeMarker against SSTI #705

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b4d312f
fix: SSTI freemarker
AT190510-Cuong Oct 23, 2025
396a5ea
fix: Harden FreeMarker SSTI
AT190510-Cuong Oct 24, 2025
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10 changes: 10 additions & 0 deletions .../src/main/java/fr/opensagres/xdocreport/template/freemarker/FreemarkerTemplateEngine.java
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Expand Up @@ -197,6 +197,16 @@ public void setFreemarkerConfiguration( Configuration freemarkerConfiguration )
{
}
this.freemarkerConfiguration.setLocalizedLookup( false );

// Security fix: Block dangerous class instantiation via ?new operator to prevent SSTI attacks
try
{
this.freemarkerConfiguration.setSetting( Configuration.NEW_BUILTIN_CLASS_RESOLVER_KEY, "safer" );

@angelozerr angelozerr Oct 23, 2025

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Is this constant exists in any freemarker version? I - think you should catch Exception instead of catching TemplateException

@AT190510-Cuong AT190510-Cuong Oct 24, 2025

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@angelozerr Thanks for the question!
Configuration.NEW_BUILTIN_CLASS_RESOLVER_KEY was introduced in FreeMarker 2.3.30, so it is supported in the FreeMarker version currently used in XDocReport (2.3.32).

}
catch ( TemplateException e )
{
// Ignore configuration errors to maintain compatibility
}
}

public void extractFields( Reader reader, String entryName, FieldsExtractor extractor )
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