diff --git a/log4j-parent/pom.xml b/log4j-parent/pom.xml
index 3f8c6264d33..91876e1f380 100644
--- a/log4j-parent/pom.xml
+++ b/log4j-parent/pom.xml
@@ -123,7 +123,7 @@
     <jansi.version>2.4.0</jansi.version>
     <javax-jms.version>2.0.1</javax-jms.version>
     <java-allocation-instrumenter.version>3.3.4</java-allocation-instrumenter.version>
-    <jctools.version>4.0.2</jctools.version>
+    <jctools.version>4.0.3</jctools.version>
     <je.version>18.3.12</je.version>
     <jetty.version>9.4.52.v20230823</jetty.version>
     <jmdns.version>3.5.9</jmdns.version>
diff --git a/src/changelog/.3.x.x/update_org_jctools_jctools_core.xml b/src/changelog/.3.x.x/update_org_jctools_jctools_core.xml
new file mode 100644
index 00000000000..df8fe16603e
--- /dev/null
+++ b/src/changelog/.3.x.x/update_org_jctools_jctools_core.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="http://logging.apache.org/log4j/changelog"
+       xsi:schemaLocation="http://logging.apache.org/log4j/changelog https://logging.apache.org/log4j/changelog-0.1.3.xsd"
+       type="updated">
+  <issue id="2267" link="https://github.com/apache/logging-log4j2/pull/2267"/>
+  <description format="asciidoc">Update `org.jctools:jctools-core` to version `4.0.3`</description>
+</entry>
diff --git a/src/site/_release-notes/_3.x.x.adoc b/src/site/_release-notes/_3.x.x.adoc
index 798f9e01666..d9b04bf30b9 100644
--- a/src/site/_release-notes/_3.x.x.adoc
+++ b/src/site/_release-notes/_3.x.x.adoc
@@ -42,6 +42,7 @@ This release contains...
 * Rewrote message parameter formatter with improved escape handling (https://github.com/apache/logging-log4j2/issues/1626[1626])
 * The MongoDb4 appender now supports long values to configure `collectionSize` (https://github.com/apache/logging-log4j2/issues/1747[1747])
 * Mark `JdkMapAdapterStringMap` as frozen if map is immutable. (https://github.com/apache/logging-log4j2/issues/2098[2098])
+* Fix regression in `JdkMapAdapterStringMap` performance. (https://github.com/apache/logging-log4j2/issues/2238[2238])
 * Prevents ClassCastException when trying to assign a SimpleLoggerContext to a core LoggerContext (https://issues.apache.org/jira/browse/LOG4J2-1921[LOG4J2-1921])
 * Possible NullPointerException in MongoDb4DocumentObject, MongoDbDocumentObject, DefaultNoSqlObject. (https://issues.apache.org/jira/browse/LOG4J2-3392[LOG4J2-3392])
 * Fix NPE in `CloseableThreadContext`. (https://github.com/apache/logging-log4j2/pull/1426[1426])
@@ -76,6 +77,7 @@ This release contains...
 * Update `org.assertj:assertj-core` to version `3.25.3` (https://github.com/apache/logging-log4j2/pull/2263[2263])
 * Update `org.elasticsearch.client:elasticsearch-rest-high-level-client` to version `7.17.17` (https://github.com/apache/logging-log4j2/pull/2237[2237])
 * Update `org.graalvm.truffle:truffle-api` to version `23.1.2` (https://github.com/apache/logging-log4j2/pull/2206[2206])
+* Update `org.jctools:jctools-core` to version `4.0.3` (https://github.com/apache/logging-log4j2/pull/2267[2267])
 * Update `org.junit:junit-bom` to version `5.10.2` (https://github.com/apache/logging-log4j2/pull/2260[2260])
 * Update `org.mockito:mockito-bom` to version `5.10.0` (https://github.com/apache/logging-log4j2/pull/2245[2245])
 * Update `org.slf4j:slf4j-api` to version `2.0.10` (https://github.com/apache/logging-log4j2/pull/2136[2136])