diff --git a/Garlic.cpp b/Garlic.cpp
index db50b627..ef894b67 100644
--- a/Garlic.cpp
+++ b/Garlic.cpp
@@ -308,12 +308,16 @@ namespace garlic
 		if (!session)
 		{
 			session = new GarlicRoutingSession (&destination, 32); 
+			std::unique_lock<std::mutex> l(m_SessionsMutex);
 			m_Sessions[destination.GetIdentHash ()] = session;
 		}	
 
 		I2NPMessage * ret = session->WrapSingleMessage (msg, leaseSet);
 		if (!session->GetNextTag ()) // tags have beed recreated
+		{
+			std::unique_lock<std::mutex> l(m_SessionsMutex);
 			m_CreatedSessions[session->GetFirstMsgID ()] = session;
+		}
 		return ret;
 	}
 		
diff --git a/Garlic.h b/Garlic.h
index e1259508..c120ae37 100644
--- a/Garlic.h
+++ b/Garlic.h
@@ -6,6 +6,7 @@
 #include <list>
 #include <string>
 #include <thread>
+#include <mutex>
 #include <cryptopp/osrng.h>
 #include "aes.h"
 #include "I2NPProtocol.h"
@@ -121,6 +122,7 @@ namespace garlic
 			std::thread * m_Thread;	
 			i2p::util::Queue<I2NPMessage> m_Queue;
 			// outgoing sessions
+			std::mutex m_SessionsMutex;
 			std::map<i2p::data::IdentHash, GarlicRoutingSession *> m_Sessions;
 			std::map<uint32_t, GarlicRoutingSession *> m_CreatedSessions; // msgID -> session
 			// incoming session