diff --git a/content/base/src/nsCrossSiteListenerProxy.cpp b/content/base/src/nsCrossSiteListenerProxy.cpp
index 6bcde723c62f..d79cfb158720 100644
--- a/content/base/src/nsCrossSiteListenerProxy.cpp
+++ b/content/base/src/nsCrossSiteListenerProxy.cpp
@@ -59,6 +59,7 @@
 #include "prtime.h"
 #include "nsClassHashtable.h"
 #include "nsHashKeys.h"
+#include "nsStreamUtils.h"
 
 #define PREFLIGHT_CACHE_SIZE 100
 
@@ -1002,7 +1003,8 @@ nsCORSPreflightListener::OnDataAvailable(nsIRequest *aRequest,
                                          PRUint32 sourceOffset,
                                          PRUint32 count)
 {
-  return NS_OK;
+  PRUint32 totalRead;
+  return inStr->ReadSegments(NS_DiscardSegment, nsnull, count, &totalRead);
 }
 
 NS_IMETHODIMP
diff --git a/content/base/test/file_CrossSiteXHR_server.sjs b/content/base/test/file_CrossSiteXHR_server.sjs
index e42c7232af3f..f1d9bb720a1b 100644
--- a/content/base/test/file_CrossSiteXHR_server.sjs
+++ b/content/base/test/file_CrossSiteXHR_server.sjs
@@ -151,6 +151,10 @@ function handleRequest(request, response)
     response.setHeader("Content-Type", "application/xml", false);
     response.write("<res>hello pass</res>\n");
   }
+  if (isPreflight && "preflightBody" in query) {
+    response.setHeader("Content-Type", "text/plain", false);
+    response.write(query.preflightBody);
+  }
 }
 
 function sendHttp500(response, text) {
diff --git a/content/base/test/test_CrossSiteXHR.html b/content/base/test/test_CrossSiteXHR.html
index df5abb8c3252..fef9720aa24a 100644
--- a/content/base/test/test_CrossSiteXHR.html
+++ b/content/base/test/test_CrossSiteXHR.html
@@ -567,6 +567,13 @@ function runTest() {
                  exposeHeaders: "  ,  ,,y-my-header,z-my-header,  ",
                  expectedResponseHeaders: ["y-my-header"],
                },
+               
+               // Check that sending a body in the OPTIONS response works
+               { pass: 1,
+                 method: "DELETE",
+                 allowMethods: "DELETE",
+                 preflightBody: "I'm a preflight response body",
+               },
                ];
 
   if (!runPreflightTests) {
@@ -635,6 +642,8 @@ function runTest() {
       req.url += "&responseHeaders=" + escape(test.responseHeaders.toSource());
     if (test.exposeHeaders)
       req.url += "&exposeHeaders=" + escape(test.exposeHeaders);
+    if (test.preflightBody)
+      req.url += "&preflightBody=" + escape(test.preflightBody);
 
     loaderWindow.postMessage(req.toSource(), origin);
     res = eval(yield);