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ramanathan1504 merged 2 commits into from
Sep 17, 2026
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Document location restrictions on Log4j 1 external entities #4265

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docs: document location restrictions on Log4j 1 external entities
ppkarwasz Aug 30, 2026
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ppkarwasz Sep 1, 2026
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7 changes: 7 additions & 0 deletions log4j-1.2-api/src/main/java/org/apache/log4j/xml/XmlConfiguration.java
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import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.URI;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
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* Parsing and validation errors do not stop the configuration process; they are printed as warnings to the status
* logger.
* </p>
* <p>
* Since version <strong>2.27.0</strong>, external entities are resolved through
* {@link ConfigurationSource#fromUri(URI)}, so they can only be retrieved from local files or over the protocols allowed by the
* <a href="https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.configurationAllowedProtocols">{@code log4j2.configurationAllowedProtocols}</a>
* configuration property.
* </p>
*/
public class XmlConfiguration extends Log4j1Configuration {

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7 changes: 7 additions & 0 deletions src/site/antora/modules/ROOT/pages/migrate-from-log4j1.adoc
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xref:manual/configuration.adoc#configuration-attribute-schema[`schema`]
attributes of the XML configuration format.

[NOTE]
====
Since version `2.27.0`, the external subset and other external entities can only be retrieved from local files or over the protocols allowed by the
xref:manual/systemproperties.adoc#log4j2.configurationAllowedProtocols[`log4j2.configurationAllowedProtocols`]
property.
====

[#configuration-appenders]
==== Appenders

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