diff --git a/CHANGES.txt b/CHANGES.txt
index 389ee2bb1c..d6c9ae694e 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -28,6 +28,7 @@
  * Disallow post-query re-ordering when paging (CASSANDRA-6722)
  * Fix potential paging bug with deleted columns (CASSANDRA-6748)
 Merged from 1.2:
+ * Add CMSClassUnloadingEnabled JVM option (CASSANDRA-6541)
  * Catch memtable flush exceptions during shutdown (CASSANDRA-6735)
  * Fix broken streams when replacing with same IP (CASSANDRA-6622)
  * Fix upgradesstables NPE for non-CF-based indexes (CASSANDRA-6645)
diff --git a/conf/cassandra-env.sh b/conf/cassandra-env.sh
index 78a39f4a13..934e4636cc 100644
--- a/conf/cassandra-env.sh
+++ b/conf/cassandra-env.sh
@@ -168,6 +168,9 @@ then
     JVM_OPTS="$JVM_OPTS -javaagent:$CASSANDRA_HOME/lib/jamm-0.2.5.jar"
 fi
 
+# some JVMs will fill up their heap when accessed via JMX, see CASSANDRA-6541
+JVM_OPTS="$JVM_OPTS -XX:+CMSClassUnloadingEnabled"
+
 # enable thread priorities, primarily so we can give periodic tasks
 # a lower priority to avoid interfering with client workload
 JVM_OPTS="$JVM_OPTS -XX:+UseThreadPriorities"