diff --git a/src/share/classes/com/sun/naming/internal/VersionHelper12.java b/src/share/classes/com/sun/naming/internal/VersionHelper12.java
index bf4586e7ebcf474e8fd4cd21a8e2d868eda6197e..9133c73e7a9c0394e6f7162d76d8329e281f9add 100644
--- a/src/share/classes/com/sun/naming/internal/VersionHelper12.java
+++ b/src/share/classes/com/sun/naming/internal/VersionHelper12.java
@@ -61,6 +61,25 @@ final class VersionHelper12 extends VersionHelper {
         return loadClass(className, getContextClassLoader());
     }
 
+    /**
+     * Determines whether classes may be loaded from an arbitrary URL code base.
+     */
+    private static final String TRUST_URL_CODEBASE_PROPERTY =
+            "com.sun.jndi.ldap.object.trustURLCodebase";
+    private static final String trustURLCodebase =
+            AccessController.doPrivileged(
+                new PrivilegedAction<String>() {
+                    public String run() {
+                        try {
+                        return System.getProperty(TRUST_URL_CODEBASE_PROPERTY,
+                            "false");
+                        } catch (SecurityException e) {
+                        return "false";
+                        }
+                    }
+                }
+            );
+
     /**
      * Package private.
      *
@@ -79,12 +98,15 @@ final class VersionHelper12 extends VersionHelper {
      */
     public Class<?> loadClass(String className, String codebase)
             throws ClassNotFoundException, MalformedURLException {
+        if ("true".equalsIgnoreCase(trustURLCodebase)) {
+            ClassLoader parent = getContextClassLoader();
+            ClassLoader cl =
+                    URLClassLoader.newInstance(getUrlArray(codebase), parent);
 
-        ClassLoader parent = getContextClassLoader();
-        ClassLoader cl =
-                 URLClassLoader.newInstance(getUrlArray(codebase), parent);
-
-        return loadClass(className, cl);
+            return loadClass(className, cl);
+        } else {
+            return null;
+        }
     }
 
     String getJndiProperty(final int i) {