diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 8a44a60dbe16..1c0cbf7e9b7b 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -2463,8 +2463,11 @@ nsDocument::StartDocumentLoad(const char* aCommand, nsIChannel* aChannel,
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
-  nsresult rv = InitCSP(aChannel);
-  NS_ENSURE_SUCCESS(rv, rv);
+  // If this is not a data document, set CSP.
+  if (!mLoadedAsData) {
+    nsresult rv = InitCSP(aChannel);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
 
   return NS_OK;
 }
diff --git a/content/base/test/csp/file_CSP_bug941404.html b/content/base/test/csp/file_CSP_bug941404.html
new file mode 100644
index 000000000000..94f4499c3c8a
--- /dev/null
+++ b/content/base/test/csp/file_CSP_bug941404.html
@@ -0,0 +1,27 @@
+<html>
+<head> <meta charset="utf-8"> </head>
+  <body>
+
+    <!-- this should be allowed (no CSP)-->
+    <img src="http://example.org/tests/content/base/test/csp/file_CSP.sjs?testid=img_good&type=img/png"> </img>
+
+
+    <script type="text/javascript">
+      var req = new XMLHttpRequest();
+      req.onload = function() {
+        //this should be allowed (no CSP)
+        try {
+        var img = document.createElement("img");
+        img.src="http://example.org/tests/content/base/test/csp/file_CSP.sjs?testid=img2_good&type=img/png";
+        document.body.appendChild(img);
+        } catch(e) {
+          console.log("yo: "+e);
+        }
+      };
+      req.open("get", "file_CSP_bug941404_xhr.html", true);
+      req.responseType = "document";
+      req.send();
+    </script>
+
+  </body>
+</html>
diff --git a/content/base/test/csp/file_CSP_bug941404_xhr.html b/content/base/test/csp/file_CSP_bug941404_xhr.html
new file mode 100644
index 000000000000..22e176f20889
--- /dev/null
+++ b/content/base/test/csp/file_CSP_bug941404_xhr.html
@@ -0,0 +1,5 @@
+<html>
+<head> <meta charset="utf-8"> </head>
+  <body>
+  </body>
+</html>
diff --git a/content/base/test/csp/file_CSP_bug941404_xhr.html^headers^ b/content/base/test/csp/file_CSP_bug941404_xhr.html^headers^
new file mode 100644
index 000000000000..1e5f70cc3755
--- /dev/null
+++ b/content/base/test/csp/file_CSP_bug941404_xhr.html^headers^
@@ -0,0 +1 @@
+Content-Security-Policy: default-src 'none' 'unsafe-inline' 'unsafe-eval'
diff --git a/content/base/test/csp/mochitest.ini b/content/base/test/csp/mochitest.ini
index fc9dcc91222e..9a28ce000fba 100644
--- a/content/base/test/csp/mochitest.ini
+++ b/content/base/test/csp/mochitest.ini
@@ -99,6 +99,9 @@ support-files =
   file_policyuri_regression_from_multipolicy_policy
   file_nonce_source.html
   file_nonce_source.html^headers^
+  file_CSP_bug941404.html
+  file_CSP_bug941404_xhr.html
+  file_CSP_bug941404_xhr.html^headers^
 
 [test_CSP.html]
 [test_CSP_bug663567.html]
@@ -119,3 +122,4 @@ support-files =
 [test_CSP_bug909029.html]
 [test_policyuri_regression_from_multipolicy.html]
 [test_nonce_source.html]
+[test_CSP_bug941404.html]
diff --git a/content/base/test/csp/test_CSP_bug941404.html b/content/base/test/csp/test_CSP_bug941404.html
new file mode 100644
index 000000000000..5cf1ee8c1d7d
--- /dev/null
+++ b/content/base/test/csp/test_CSP_bug941404.html
@@ -0,0 +1,115 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf-8">
+  <title>Bug 941404 - Data documents should not set CSP</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<p id="display"></p>
+<div id="content" style="display: none">
+
+
+</div>
+
+<iframe style="width:200px;height:200px;" id='cspframe'></iframe>
+<script class="testbody" type="text/javascript">
+
+
+var path = "/tests/content/base/test/csp/";
+
+// These are test results: -1 means it hasn't run,
+// true/false is the pass/fail result.
+window.tests = {
+  img_good: -1,
+  img2_good: -1,
+};
+
+
+//csp related
+
+// This is used to watch the blocked data bounce off CSP and allowed data
+// get sent out to the wire.
+function examiner() {
+  SpecialPowers.addObserver(this, "csp-on-violate-policy", false);
+  SpecialPowers.addObserver(this, "http-on-modify-request", false);
+}
+
+examiner.prototype  = {
+  observe: function(subject, topic, data) {
+    // subject should be an nsURI, and should be either allowed or blocked.
+    if (!SpecialPowers.can_QI(subject))
+      return;
+
+    var testpat = new RegExp("testid=([a-z0-9_]+)");
+
+    //_good things better be allowed!
+    //_bad things better be stopped!
+
+    if (topic === "http-on-modify-request") {
+      //these things were allowed by CSP
+      var asciiSpec = SpecialPowers.getPrivilegedProps(SpecialPowers.do_QueryInterface(subject, "nsIHttpChannel"), "URI.asciiSpec");
+      if (!testpat.test(asciiSpec)) return;
+      var testid = testpat.exec(asciiSpec)[1];
+
+      window.testResult(testid,
+                        /_good/.test(testid),
+                        asciiSpec + " allowed by csp");
+    }
+
+    if(topic === "csp-on-violate-policy") {
+      //these were blocked... record that they were blocked
+      var asciiSpec = SpecialPowers.getPrivilegedProps(SpecialPowers.do_QueryInterface(subject, "nsIURI"), "asciiSpec");
+      if (!testpat.test(asciiSpec)) return;
+      var testid = testpat.exec(asciiSpec)[1];
+      window.testResult(testid,
+                        /_bad/.test(testid),
+                        asciiSpec + " blocked by \"" + data + "\"");
+    }
+  },
+
+  // must eventually call this to remove the listener,
+  // or mochitests might get borked.
+  remove: function() {
+    SpecialPowers.removeObserver(this, "csp-on-violate-policy");
+    SpecialPowers.removeObserver(this, "http-on-modify-request");
+  }
+}
+
+window.examiner = new examiner();
+
+window.testResult = function(testname, result, msg) {
+  //test already complete.... forget it... remember the first result.
+  if (window.tests[testname] != -1)
+    return;
+
+  window.tests[testname] = result;
+  is(result, true, testname + ' test: ' + msg);
+
+  // if any test is incomplete, keep waiting
+  for (var v in window.tests)
+    if(tests[v] == -1) {
+      console.log(v + " is not complete");
+      return;
+    }
+
+  // ... otherwise, finish
+  window.examiner.remove();
+  SimpleTest.finish();
+}
+
+SimpleTest.waitForExplicitFinish();
+
+SpecialPowers.pushPrefEnv(
+  {'set':[["security.csp.speccompliant", true]]},
+  function() {
+    // save this for last so that our listeners are registered.
+    // ... this loads the testbed of good and bad requests.
+    document.getElementById('cspframe').src = 'file_CSP_bug941404.html';
+  });
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/testing/mochitest/b2g.json b/testing/mochitest/b2g.json
index 90eeee181578..a570013b2451 100644
--- a/testing/mochitest/b2g.json
+++ b/testing/mochitest/b2g.json
@@ -214,6 +214,7 @@
     "content/base/test/csp/test_CSP_bug909029.html":"observer not working",
     "content/base/test/csp/test_policyuri_regression_from_multipolicy.html":"observer not working",
     "content/base/test/csp/test_nonce_source.html":"observer not working",
+    "content/base/test/csp/test_CSP_bug941404.html":"observer not working",
 
     "content/base/test/test_CrossSiteXHR_origin.html":"https not working, bug 907770",
     "content/base/test/test_plugin_freezing.html":"",
