Index: core/src/main/java/hudson/model/AbstractProject.java
===================================================================
--- core/src/main/java/hudson/model/AbstractProject.java	(revision 18218)
+++ core/src/main/java/hudson/model/AbstractProject.java	(working copy)
@@ -1266,6 +1266,7 @@
     }
 
     public void doEnable(StaplerResponse rsp) throws IOException, ServletException {
+        requirePOST();
         checkPermission(CONFIGURE);
         makeDisabled(false);
         rsp.sendRedirect2(".");