--- a/media/gmp-clearkey/0.1/ClearKeySession.cpp
+++ b/media/gmp-clearkey/0.1/ClearKeySession.cpp
@@ -65,17 +65,17 @@ ClearKeySession::Init(uint32_t aCreateSe
   } else if (aInitDataType == "keyids") {
     std::string sessionType;
     ClearKeyUtils::ParseKeyIdsInitData(aInitData, aInitDataSize, mKeyIds, sessionType);
     if (sessionType != ClearKeyUtils::SessionTypeToString(mSessionType)) {
       const char message[] = "Session type specified in keyids init data doesn't match session type.";
       mCallback->RejectPromise(aPromiseId, kGMPInvalidAccessError, message, strlen(message));
       return;
     }
-  } else if (aInitDataType == "webm") {
+  } else if (aInitDataType == "webm" && aInitDataSize <= kMaxWebmInitDataSize) {
     // "webm" initData format is simply the raw bytes of the keyId.
     vector<uint8_t> keyId;
     keyId.assign(aInitData, aInitData+aInitDataSize);
     mKeyIds.push_back(keyId);
   }
 
   if (!mKeyIds.size()) {
     const char message[] = "Couldn't parse init data";

--- a/media/gmp-clearkey/0.1/ClearKeyUtils.cpp
+++ b/media/gmp-clearkey/0.1/ClearKeyUtils.cpp
@@ -440,17 +440,17 @@ ParseKeyIds(ParserContext& aCtx, vector<
   EXPECT_SYMBOL(aCtx, '[');
 
   while (true) {
     string label;
     vector<uint8_t> keyId;
     if (!GetNextLabel(aCtx, label) || !DecodeBase64(label, keyId)) {
       return false;
     }
-    if (!keyId.empty()) {
+    if (!keyId.empty() && keyId.size() <= kMaxKeyIdsLength) {
       aOutKeyIds.push_back(keyId);
     }
 
     uint8_t sym = PeekSymbol(aCtx);
     if (!sym || sym == ']') {
       break;
     }
 

--- a/media/gmp-clearkey/0.1/ClearKeyUtils.h
+++ b/media/gmp-clearkey/0.1/ClearKeyUtils.h
@@ -35,16 +35,20 @@ void CK_Log(const char* aFmt, ...);
 #endif
 
 struct GMPPlatformAPI;
 extern GMPPlatformAPI* GetPlatform();
 
 typedef std::vector<uint8_t> KeyId;
 typedef std::vector<uint8_t> Key;
 
+// Provide limitation for KeyIds length and webm initData size.
+static const uint32_t kMaxWebmInitDataSize = 65536;
+static const uint32_t kMaxKeyIdsLength = 512;
+
 struct KeyIdPair
 {
   KeyId mKeyId;
   Key mKey;
 };
 
 class ClearKeyUtils
 {

deleted file mode 100644
--- a/testing/web-platform/meta/encrypted-media/Google/encrypted-media-keystatuses-multiple-sessions.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[encrypted-media-keystatuses-multiple-sessions.html]
-  type: testharness
-  [Verify MediaKeySession.keyStatuses with multiple sessions.]
-    expected: TIMEOUT
-

deleted file mode 100644
--- a/testing/web-platform/meta/encrypted-media/Google/encrypted-media-keystatuses-multiple-updates.html.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[encrypted-media-keystatuses-multiple-updates.html]
-  type: testharness
-  [Verify MediaKeySession.keyStatuses with multiple updates.]
-    expected: TIMEOUT
-

--- a/testing/web-platform/meta/encrypted-media/Google/encrypted-media-keystatuses.html.ini
+++ b/testing/web-platform/meta/encrypted-media/Google/encrypted-media-keystatuses.html.ini
@@ -1,5 +1,4 @@
 [encrypted-media-keystatuses.html]
   type: testharness
   [Verify MediaKeySession.keyStatuses.]
-    expected: TIMEOUT
-
+    expected: FAIL

--- a/testing/web-platform/meta/encrypted-media/Google/encrypted-media-syntax.html.ini
+++ b/testing/web-platform/meta/encrypted-media/Google/encrypted-media-syntax.html.ini
@@ -7,20 +7,16 @@
     expected: TIMEOUT
 
   [Test MediaKeys load() exceptions.]
     expected: TIMEOUT
 
   [Test MediaKeySession update() exceptions.]
     expected: TIMEOUT
 
-  [Test MediaKeySession update().]
-    expected: TIMEOUT
-
   [Test MediaKeySession close().]
     expected: TIMEOUT
 
   [Test MediaKeys setServerCertificate() exceptions.]
     expected: TIMEOUT
 
   [Test MediaKeys setServerCertificate().]
     expected: TIMEOUT
-