diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 4e37c55b85b..7c0d4a007b8 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -150,6 +150,8 @@ Release 0.23.1 - Unreleased
    HADOOP-7864. Building mvn site with Maven < 3.0.2 causes OOM errors.
    (Andrew Bayer via eli)
 
+   HADOOP-7854. UGI getCurrentUser is not synchronized. (Daryn Sharp via jitendra)
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
index 344c08e2b66..b272e80fac6 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
@@ -449,7 +449,8 @@ public class UserGroupInformation {
    * @return the current user
    * @throws IOException if login fails
    */
-  public static UserGroupInformation getCurrentUser() throws IOException {
+  public synchronized
+  static UserGroupInformation getCurrentUser() throws IOException {
     AccessControlContext context = AccessController.getContext();
     Subject subject = Subject.getSubject(context);
     if (subject == null || subject.getPrincipals(User.class).isEmpty()) {