diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index eeb53b82975..ad1cd2dd526 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -64,6 +64,9 @@ New Features
 
 Bug Fixes
 
+* LUCENE-6368: FST.save can truncate output (BufferedOutputStream may be closed 
+  after the underlying stream). (Ippei Matsushima via Dawid Weiss)
+
 * LUCENE-6249: StandardQueryParser doesn't support pure negative clauses. 
   (Dawid Weiss)
   
diff --git a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
index 552e5135d6d..1cf2f04229e 100644
--- a/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
+++ b/lucene/core/src/java/org/apache/lucene/util/fst/FST.java
@@ -605,8 +605,8 @@ public final class FST<T> implements Accountable {
    * Writes an automaton to a file. 
    */
   public void save(final Path path) throws IOException {
-    try (OutputStream os = Files.newOutputStream(path)) {
-      save(new OutputStreamDataOutput(new BufferedOutputStream(os)));
+    try (OutputStream os = new BufferedOutputStream(Files.newOutputStream(path))) {
+      save(new OutputStreamDataOutput(os));
     }
   }