diff --git a/dom/security/test/cors/test_CrossSiteXHR_cache.html b/dom/security/test/cors/test_CrossSiteXHR_cache.html
index 437c9d9d8b7f..77898e38edcb 100644
--- a/dom/security/test/cors/test_CrossSiteXHR_cache.html
+++ b/dom/security/test/cors/test_CrossSiteXHR_cache.html
@@ -63,7 +63,7 @@ function* runTest() {
              headers: { "y-my-header": "hello" },
              allowHeaders: "y-my-header",
            },
-           { pass: 0,
+           { pass: 1,
              method: "GET",
              headers: { "y-my-header": "hello" },
            },
@@ -73,6 +73,21 @@ function* runTest() {
              allowHeaders: "y-my-header,x-my-header",
              cacheTime: 3600,
            },
+           { pass: 0,
+             method: "GET",
+             headers: { "x-my-header": "myValue",
+                        "y-my-header": "second" },
+           },
+           { newTest: "*******" },
+           { pass: 1,
+             method: "GET",
+             headers: { "y-my-header": "hello" },
+             allowHeaders: "y-my-header,x-my-header",
+           },
+           { pass: 1,
+             method: "GET",
+             headers: { "y-my-header": "hello" },
+           },
            { pass: 1,
              method: "GET",
              headers: { "x-my-header": "myValue",
@@ -224,7 +239,7 @@ function* runTest() {
              method: "PATCH",
              allowMethods: "PATCH",
            },
-           { pass: 0,
+           { pass: 1,
              method: "PATCH",
            },
            { pass: 1,
@@ -242,6 +257,15 @@ function* runTest() {
              method: "PUT",
            },
            { newTest: "*******" },
+           { pass: 1,
+             method: "PATCH",
+             allowMethods: "PATCH",
+             cacheTime: 3600,
+           },
+           { pass: 1,
+             method: "PATCH",
+           },
+           { newTest: "*******" },
            { pass: 0,
              method: "DELETE",
            },
diff --git a/netwerk/protocol/http/nsCORSListenerProxy.cpp b/netwerk/protocol/http/nsCORSListenerProxy.cpp
index 938eba5c92d0..8a6f222ad08d 100644
--- a/netwerk/protocol/http/nsCORSListenerProxy.cpp
+++ b/netwerk/protocol/http/nsCORSListenerProxy.cpp
@@ -50,6 +50,8 @@ using namespace mozilla;
 using namespace mozilla::net;
 
 #define PREFLIGHT_CACHE_SIZE 100
+// 5 seconds is chosen to be compatible with Chromium.
+#define PREFLIGHT_DEFAULT_EXPIRY_SECONDS 5
 
 static void LogBlockedRequest(nsIRequest* aRequest, const char* aProperty,
                               const char16_t* aParam, uint32_t aBlockingReason,
@@ -1112,27 +1114,27 @@ void nsCORSPreflightListener::AddResultToCache(nsIRequest* aRequest) {
 
   // The "Access-Control-Max-Age" header should return an age in seconds.
   nsAutoCString headerVal;
+  uint32_t age = 0;
   Unused << http->GetResponseHeader(
       NS_LITERAL_CSTRING("Access-Control-Max-Age"), headerVal);
   if (headerVal.IsEmpty()) {
-    return;
-  }
-
-  // Sanitize the string. We only allow 'delta-seconds' as specified by
-  // http://dev.w3.org/2006/waf/access-control (digits 0-9 with no leading or
-  // trailing non-whitespace characters).
-  uint32_t age = 0;
-  nsACString::const_char_iterator iter, end;
-  headerVal.BeginReading(iter);
-  headerVal.EndReading(end);
-  while (iter != end) {
-    if (*iter < '0' || *iter > '9') {
-      return;
+    age = PREFLIGHT_DEFAULT_EXPIRY_SECONDS;
+  } else {
+    // Sanitize the string. We only allow 'delta-seconds' as specified by
+    // http://dev.w3.org/2006/waf/access-control (digits 0-9 with no leading or
+    // trailing non-whitespace characters).
+    nsACString::const_char_iterator iter, end;
+    headerVal.BeginReading(iter);
+    headerVal.EndReading(end);
+    while (iter != end) {
+      if (*iter < '0' || *iter > '9') {
+        return;
+      }
+      age = age * 10 + (*iter - '0');
+      // Cap at 24 hours. This also avoids overflow
+      age = std::min(age, 86400U);
+      ++iter;
     }
-    age = age * 10 + (*iter - '0');
-    // Cap at 24 hours. This also avoids overflow
-    age = std::min(age, 86400U);
-    ++iter;
   }
 
   if (!age || !EnsurePreflightCache()) {
diff --git a/testing/web-platform/meta/cors/preflight-cache.htm.ini b/testing/web-platform/meta/cors/preflight-cache.htm.ini
deleted file mode 100644
index 2f52e604fb5a..000000000000
--- a/testing/web-platform/meta/cors/preflight-cache.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[preflight-cache.htm]
-  [preflight for x-print should be cached]
-    expected: FAIL
-
diff --git a/testing/web-platform/tests/cors/preflight-cache.htm b/testing/web-platform/tests/cors/preflight-cache.htm
index 0b6138bdffac..b3de663ebc1d 100644
--- a/testing/web-platform/tests/cors/preflight-cache.htm
+++ b/testing/web-platform/tests/cors/preflight-cache.htm
@@ -60,6 +60,15 @@ test(function() {
 },
 'preflight for x-print should be cached')
 
+test(function() {
+    var time = new Date().getTime()
+    var client = new XMLHttpRequest()
+
+    var id = did_preflight(true, client, {extra:'max_age='})
+    did_preflight(false, client, {extra:'max_age=', token: id})
+},
+'age = blank, should be cached')
+
 test(function() {
     var time = new Date().getTime()
     var client = new XMLHttpRequest()