diff --git a/dependency-check-core/src/main/java/org/owasp/dependencycheck/data/cpe/CpeMemoryIndex.java b/dependency-check-core/src/main/java/org/owasp/dependencycheck/data/cpe/CpeMemoryIndex.java
index 857abb6cc..c330cc3e1 100644
--- a/dependency-check-core/src/main/java/org/owasp/dependencycheck/data/cpe/CpeMemoryIndex.java
+++ b/dependency-check-core/src/main/java/org/owasp/dependencycheck/data/cpe/CpeMemoryIndex.java
@@ -62,7 +62,7 @@ public final class CpeMemoryIndex {
     /**
      * singleton instance.
      */
-    private static CpeMemoryIndex instance = new CpeMemoryIndex();
+    private static final CpeMemoryIndex INSTANCE = new CpeMemoryIndex();
 
     /**
      * private constructor for singleton.
@@ -76,7 +76,7 @@ public final class CpeMemoryIndex {
      * @return the instance of the CpeMemoryIndex
      */
     public static CpeMemoryIndex getInstance() {
-        return instance;
+        return INSTANCE;
     }
     /**
      * The in memory Lucene index.
@@ -114,18 +114,20 @@ public final class CpeMemoryIndex {
      * @throws IndexException thrown if there is an error creating the index
      */
     public void open(CveDB cve) throws IndexException {
-        if (!openState) {
-            index = new RAMDirectory();
-            buildIndex(cve);
-            try {
-                indexReader = DirectoryReader.open(index);
-            } catch (IOException ex) {
-                throw new IndexException(ex);
+        synchronized (INSTANCE) {
+            if (!openState) {
+                index = new RAMDirectory();
+                buildIndex(cve);
+                try {
+                    indexReader = DirectoryReader.open(index);
+                } catch (IOException ex) {
+                    throw new IndexException(ex);
+                }
+                indexSearcher = new IndexSearcher(indexReader);
+                searchingAnalyzer = createSearchingAnalyzer();
+                queryParser = new QueryParser(LuceneUtils.CURRENT_VERSION, Fields.DOCUMENT_KEY, searchingAnalyzer);
+                openState = true;
             }
-            indexSearcher = new IndexSearcher(indexReader);
-            searchingAnalyzer = createSearchingAnalyzer();
-            queryParser = new QueryParser(LuceneUtils.CURRENT_VERSION, Fields.DOCUMENT_KEY, searchingAnalyzer);
-            openState = true;
         }
     }
     /**