diff --git a/dependency-check-ant/src/main/java/org/owasp/dependencycheck/taskdefs/Check.java b/dependency-check-ant/src/main/java/org/owasp/dependencycheck/taskdefs/Check.java
index a7b3b4049..3b086ab3f 100644
--- a/dependency-check-ant/src/main/java/org/owasp/dependencycheck/taskdefs/Check.java
+++ b/dependency-check-ant/src/main/java/org/owasp/dependencycheck/taskdefs/Check.java
@@ -1014,7 +1014,7 @@ public class Check extends Update {
      *
      * @throws BuildException if the task was not configured correctly.
      */
-    private void validateConfiguration() throws BuildException {
+    private synchronized void validateConfiguration() throws BuildException {
         if (path == null) {
             throw new BuildException("No project dependencies have been defined to analyze.");
         }
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 2641bf8f5..3132778b4 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
@@ -137,7 +137,7 @@ public final class CpeMemoryIndex {
      *
      * @return whether or not the index is open
      */
-    public boolean isOpen() {
+    public synchronized boolean isOpen() {
         return openState;
     }
 
@@ -274,7 +274,7 @@ public final class CpeMemoryIndex {
      * @return the Document
      * @throws IOException thrown if there is an IOException
      */
-    public Document getDocument(int documentId) throws IOException {
+    public synchronized Document getDocument(int documentId) throws IOException {
         return indexSearcher.doc(documentId);
     }
 
@@ -283,7 +283,7 @@ public final class CpeMemoryIndex {
      *
      * @return the number of CPE entries stored in the index
      */
-    public int numDocs() {
+    public synchronized int numDocs() {
         if (indexReader == null) {
             return -1;
         }