diff --git a/NetDb.cpp b/NetDb.cpp
index 411b381e..4aa48be4 100644
--- a/NetDb.cpp
+++ b/NetDb.cpp
@@ -182,7 +182,10 @@ namespace data
 			RouterInfo * r = new RouterInfo (buf, len);
 			m_RouterInfos[r->GetIdentHash ()] = r;
 			if (r->IsFloodfill ())
+			{
+				std::unique_lock<std::mutex> l(m_FloodfillsMutex);
 				m_Floodfills.push_back (r);
+			}	
 		}	
 	}	
 
@@ -852,6 +855,7 @@ namespace data
 		XORMetric minMetric;
 		RoutingKey destKey = CreateRoutingKey (destination);
 		minMetric.SetMax ();
+		std::unique_lock<std::mutex> l(m_FloodfillsMutex);
 		for (auto it: m_Floodfills)
 		{	
 			if (!it->IsUnreachable () && !excluded.count (it->GetIdentHash ()))
diff --git a/NetDb.h b/NetDb.h
index 31bd05fa..523f5c81 100644
--- a/NetDb.h
+++ b/NetDb.h
@@ -7,6 +7,7 @@
 #include <vector>
 #include <string>
 #include <thread>
+#include <mutex>
 #include <boost/filesystem.hpp>
 #include "Queue.h"
 #include "I2NPProtocol.h"
@@ -114,6 +115,7 @@ namespace data
 
 			std::map<IdentHash, LeaseSet *> m_LeaseSets;
 			std::map<IdentHash, RouterInfo *> m_RouterInfos;
+			mutable std::mutex m_FloodfillsMutex;
 			std::vector<RouterInfo *> m_Floodfills;
 			std::mutex m_RequestedDestinationsMutex;
 			std::map<IdentHash, RequestedDestination *> m_RequestedDestinations;
diff --git a/SAM.cpp b/SAM.cpp
index c647e246..15733c45 100644
--- a/SAM.cpp
+++ b/SAM.cpp
@@ -582,6 +582,7 @@ namespace stream
 		{
 			SAMSession session;
 			session.localDestination = localDestination;
+			std::unique_lock<std::mutex> l(m_SessionsMutex);
 			auto ret = m_Sessions.insert (std::pair<std::string, SAMSession>(id, session));
 			if (!ret.second)
 				LogPrint ("Session ", id, " already exists");
@@ -592,6 +593,7 @@ namespace stream
 
 	void SAMBridge::CloseSession (const std::string& id)
 	{
+		std::unique_lock<std::mutex> l(m_SessionsMutex);
 		auto it = m_Sessions.find (id);
 		if (it != m_Sessions.end ())
 		{
@@ -605,6 +607,7 @@ namespace stream
 
 	SAMSession * SAMBridge::FindSession (const std::string& id)
 	{
+		std::unique_lock<std::mutex> l(m_SessionsMutex);
 		auto it = m_Sessions.find (id);
 		if (it != m_Sessions.end ())
 			return &it->second;
diff --git a/SAM.h b/SAM.h
index 883c817c..7a42ac8f 100644
--- a/SAM.h
+++ b/SAM.h
@@ -6,6 +6,7 @@
 #include <map>
 #include <list>
 #include <thread>
+#include <mutex>
 #include <boost/asio.hpp>
 #include "Identity.h"
 #include "LeaseSet.h"
@@ -144,6 +145,7 @@ namespace stream
 			boost::asio::io_service m_Service;
 			boost::asio::ip::tcp::acceptor m_Acceptor;
 			SAMSocket * m_NewSocket;
+			std::mutex m_SessionsMutex;
 			std::map<std::string, SAMSession> m_Sessions;
 	};		
 }