diff --git a/src/core/coap/coap_server.hpp b/src/core/coap/coap_server.hpp
index c3c57a72e..1c929829a 100644
--- a/src/core/coap/coap_server.hpp
+++ b/src/core/coap/coap_server.hpp
@@ -80,6 +80,7 @@ public:
         mUriPath = aUriPath;
         mHandler = aHandler;
         mContext = aContext;
+        mNext = NULL;
     }
 
 private:
diff --git a/src/core/common/timer.hpp b/src/core/common/timer.hpp
index 82c0a8480..a44066b50 100644
--- a/src/core/common/timer.hpp
+++ b/src/core/common/timer.hpp
@@ -136,7 +136,13 @@ public:
      * @param[in]  aContext  A pointer to arbitrary context information.
      *
      */
-    Timer(Handler aHandler, void *aContext) { mNext = NULL; mHandler = aHandler; mContext = aContext; }
+    Timer(Handler aHandler, void *aContext) {
+        mHandler = aHandler;
+        mContext = aContext;
+        mT0 = 0;
+        mDt = 0;
+        mNext = NULL;
+    }
 
     /**
      * This method returns the start time in milliseconds for the timer.
diff --git a/src/core/net/icmp6.hpp b/src/core/net/icmp6.hpp
index e7007da52..8951e8c21 100644
--- a/src/core/net/icmp6.hpp
+++ b/src/core/net/icmp6.hpp
@@ -294,6 +294,7 @@ public:
     IcmpHandler(DstUnreachHandler aDstUnreachHandler, void *aContext) {
         mDstUnreachHandler = aDstUnreachHandler;
         mContext = aContext;
+        mNext = NULL;
     }
 
 private:
@@ -303,9 +304,9 @@ private:
 
     DstUnreachHandler    mDstUnreachHandler;
     void                *mContext;
-    IcmpHandler        *mNext;
+    IcmpHandler         *mNext;
 
-    static IcmpHandler *sHandlers;
+    static IcmpHandler  *sHandlers;
 };
 
 /**
diff --git a/src/core/thread/key_manager.cpp b/src/core/thread/key_manager.cpp
index 0bcbf8967..37acc8526 100644
--- a/src/core/thread/key_manager.cpp
+++ b/src/core/thread/key_manager.cpp
@@ -48,8 +48,11 @@ KeyManager::KeyManager(ThreadNetif &aThreadNetif):
     mNetif(aThreadNetif)
 {
     mPreviousKeyValid = false;
+    mMasterKeyLength = 0;
     mMacFrameCounter = 0;
     mMleFrameCounter = 0;
+    mCurrentKeySequence = 0;
+    mPreviousKeySequence = 0;
 }
 
 const uint8_t *KeyManager::GetMasterKey(uint8_t *aKeyLength) const
diff --git a/src/core/thread/mesh_forwarder.cpp b/src/core/thread/mesh_forwarder.cpp
index 5326d4b6e..ef1af8cc7 100644
--- a/src/core/thread/mesh_forwarder.cpp
+++ b/src/core/thread/mesh_forwarder.cpp
@@ -68,6 +68,13 @@ MeshForwarder::MeshForwarder(ThreadNetif &aThreadNetif):
     mSendBusy = false;
     mEnabled = false;
 
+    mMessageNextOffset = 0;
+    mMacSource.mLength = 0;
+    mMacDest.mLength = 0;
+    mMeshSource = Mac::kShortAddrInvalid;
+    mMeshDest = Mac::kShortAddrInvalid;
+    mAddMeshHeader = false;
+
     mMac.RegisterReceiver(mMacReceiver);
 }
 
diff --git a/src/core/thread/mle.cpp b/src/core/thread/mle.cpp
index 205665715..1fb031505 100644
--- a/src/core/thread/mle.cpp
+++ b/src/core/thread/mle.cpp
@@ -66,6 +66,7 @@ Mle::Mle(ThreadNetif &aThreadNetif) :
                   ModeTlv::kModeFullNetworkData;
     mParentRequestState = kParentIdle;
     mParentRequestMode = kMleAttachAnyPartition;
+    mParentConnectivity = 0;
     mTimeout = kMaxNeighborAge;
 
     memset(&mLeaderData, 0, sizeof(mLeaderData));
@@ -209,6 +210,7 @@ ThreadError Mle::BecomeChild(otMleAttachFilter aFilter)
 
     mParentRequestState = kParentRequestStart;
     mParentRequestMode = aFilter;
+    mParentConnectivity = 0;
     memset(&mParent, 0, sizeof(mParent));
 
     if (aFilter == kMleAttachAnyPartition)
diff --git a/src/core/thread/mle_router.cpp b/src/core/thread/mle_router.cpp
index 03be94466..123af6bfd 100644
--- a/src/core/thread/mle_router.cpp
+++ b/src/core/thread/mle_router.cpp
@@ -67,6 +67,7 @@ MleRouter::MleRouter(ThreadNetif &aThreadNetif):
     mRouterId = kMaxRouterId;
     mPreviousRouterId = kMaxRouterId;
     mAdvertiseInterval = kAdvertiseIntervalMin;
+    mRouterIdSequenceLastUpdated = 0;
 
     mCoapMessageId = otPlatRandomGet();
 }
diff --git a/src/core/thread/network_data_local.cpp b/src/core/thread/network_data_local.cpp
index 8710ca157..db4e3a2fa 100644
--- a/src/core/thread/network_data_local.cpp
+++ b/src/core/thread/network_data_local.cpp
@@ -48,6 +48,7 @@ Local::Local(ThreadNetif &aThreadNetif):
     NetworkData(),
     mMle(aThreadNetif.GetMle())
 {
+    mCoapMessageId = 0;
 }
 
 ThreadError Local::AddOnMeshPrefix(const uint8_t *aPrefix, uint8_t aPrefixLength, int8_t aPrf,