diff --git a/toolkit/components/places/AsyncFaviconHelpers.cpp b/toolkit/components/places/AsyncFaviconHelpers.cpp
index c01e5faf05cc..3bdb96ee7c67 100644
--- a/toolkit/components/places/AsyncFaviconHelpers.cpp
+++ b/toolkit/components/places/AsyncFaviconHelpers.cpp
@@ -635,9 +635,21 @@ AsyncFetchAndSetIconFromNetwork::OnStopRequest(nsIRequest* aRequest,
     return NS_OK;
   }
 
-  NS_SniffContent(NS_DATA_SNIFFER_CATEGORY, aRequest,
-                  TO_INTBUFFER(mIcon.data), mIcon.data.Length(),
-                  mIcon.mimeType);
+  nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
+  // aRequest should always QI to nsIChannel.
+  // See AsyncFetchAndSetIconFromNetwork::Run()
+  MOZ_ASSERT(channel);
+
+  nsAutoCString contentType;
+  channel->GetContentType(contentType);
+  // Bug 366324 - can't sniff SVG yet, so rely on server-specified type
+  if (contentType.EqualsLiteral("image/svg+xml")) {
+    mIcon.mimeType.AssignLiteral("image/svg+xml");
+  } else {
+    NS_SniffContent(NS_DATA_SNIFFER_CATEGORY, aRequest,
+                    TO_INTBUFFER(mIcon.data), mIcon.data.Length(),
+                    mIcon.mimeType);
+  }
 
   // If the icon does not have a valid MIME type, add it to the failed cache.
   if (mIcon.mimeType.IsEmpty()) {
@@ -649,10 +661,6 @@ AsyncFetchAndSetIconFromNetwork::OnStopRequest(nsIRequest* aRequest,
     return NS_OK;
   }
 
-  nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
-  // aRequest should always QI to nsIChannel.
-  // See AsyncFetchAndSetIconFromNetwork::Run()
-  MOZ_ASSERT(channel);
   mIcon.expiration = GetExpirationTimeFromChannel(channel);
 
   // Telemetry probes to measure the favicon file sizes for each different file type.
diff --git a/toolkit/components/places/tests/head_common.js b/toolkit/components/places/tests/head_common.js
index e5320846d9d1..f2f216c5e2b8 100644
--- a/toolkit/components/places/tests/head_common.js
+++ b/toolkit/components/places/tests/head_common.js
@@ -57,6 +57,16 @@ XPCOMUtils.defineLazyGetter(this, "SMALLPNG_DATA_URI", function() {
          "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAA" +
          "AAAA6fptVAAAACklEQVQI12NgAAAAAgAB4iG8MwAAAABJRU5ErkJggg==");
 });
+XPCOMUtils.defineLazyGetter(this, "SMALLSVG_DATA_URI", function() {
+  return NetUtil.newURI(
+         "data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy5" +
+         "3My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAxMDAgMTAwIiBmaWxs" +
+         "PSIjNDI0ZTVhIj4NCiAgPGNpcmNsZSBjeD0iNTAiIGN5PSI1MCIgcj0iN" +
+         "DQiIHN0cm9rZT0iIzQyNGU1YSIgc3Ryb2tlLXdpZHRoPSIxMSIgZmlsbD" +
+         "0ibm9uZSIvPg0KICA8Y2lyY2xlIGN4PSI1MCIgY3k9IjI0LjYiIHI9IjY" +
+         "uNCIvPg0KICA8cmVjdCB4PSI0NSIgeT0iMzkuOSIgd2lkdGg9IjEwLjEi" +
+         "IGhlaWdodD0iNDEuOCIvPg0KPC9zdmc%2BDQo%3D");
+});
 
 let gTestDir = do_get_cwd();
 
diff --git a/toolkit/components/places/tests/unit/test_svg_favicon.js b/toolkit/components/places/tests/unit/test_svg_favicon.js
new file mode 100644
index 000000000000..98b2e76a5e39
--- /dev/null
+++ b/toolkit/components/places/tests/unit/test_svg_favicon.js
@@ -0,0 +1,30 @@
+const PAGEURI = NetUtil.newURI("http://deliciousbacon.com/");
+
+add_task(function* () {
+  // First, add a history entry or else Places can't save a favicon.
+  yield PlacesTestUtils.addVisits({
+    uri: PAGEURI,
+    transition: TRANSITION_LINK,
+    visitDate: Date.now() * 1000
+  });
+
+  yield new Promise(resolve => {
+    function onSetComplete(aURI, aDataLen, aData, aMimeType) {
+      equal(aURI.spec, SMALLSVG_DATA_URI.spec, "setFavicon aURI check");
+      equal(aDataLen, 263, "setFavicon aDataLen check");
+      equal(aMimeType, "image/svg+xml", "setFavicon aMimeType check");
+      resolve();
+    }
+
+    PlacesUtils.favicons.setAndFetchFaviconForPage(PAGEURI, SMALLSVG_DATA_URI,
+                                                   false,
+                                                   PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
+                                                   onSetComplete);
+  });
+
+  let data = yield PlacesUtils.promiseFaviconData(PAGEURI.spec);
+  equal(data.uri.spec, SMALLSVG_DATA_URI.spec, "getFavicon aURI check");
+  equal(data.dataLen, 263, "getFavicon aDataLen check");
+  equal(data.mimeType, "image/svg+xml", "getFavicon aMimeType check");
+});
+
diff --git a/toolkit/components/places/tests/unit/xpcshell.ini b/toolkit/components/places/tests/unit/xpcshell.ini
index 72a910008ab5..eb96a097a320 100644
--- a/toolkit/components/places/tests/unit/xpcshell.ini
+++ b/toolkit/components/places/tests/unit/xpcshell.ini
@@ -138,6 +138,7 @@ skip-if = os == "android"
 [test_resolveNullBookmarkTitles.js]
 [test_result_sort.js]
 [test_sql_guid_functions.js]
+[test_svg_favicon.js]
 [test_tag_autocomplete_search.js]
 [test_tagging.js]
 [test_telemetry.js]