diff --git a/core/src/main/scala/com/nutomic/ensichat/core/header/AbstractHeader.scala b/core/src/main/scala/com/nutomic/ensichat/core/header/AbstractHeader.scala
index 97e1073..70a4752 100644
--- a/core/src/main/scala/com/nutomic/ensichat/core/header/AbstractHeader.scala
+++ b/core/src/main/scala/com/nutomic/ensichat/core/header/AbstractHeader.scala
@@ -10,6 +10,8 @@ object AbstractHeader {
 
   val InitialForwardingTokens = 3
 
+  val MaxForwardingTokens = 6
+
   val Version = 0
 
   private[header] val Length = 10 + 2 * Address.Length
diff --git a/core/src/main/scala/com/nutomic/ensichat/core/header/MessageHeader.scala b/core/src/main/scala/com/nutomic/ensichat/core/header/MessageHeader.scala
index 2f859a4..3b9a240 100644
--- a/core/src/main/scala/com/nutomic/ensichat/core/header/MessageHeader.scala
+++ b/core/src/main/scala/com/nutomic/ensichat/core/header/MessageHeader.scala
@@ -24,6 +24,8 @@ object MessageHeader {
       throw new ReadMessageException("Failed to parse message with unsupported version " + version)
     val protocolType = BufferUtils.getUnsignedByte(b)
     val tokens = BufferUtils.getUnsignedByte(b)
+    if (tokens > AbstractHeader.MaxForwardingTokens)
+      throw new ReadMessageException(s"Received message with too many forwarding tokens ($tokens tokens)")
     val hopCount = BufferUtils.getUnsignedByte(b)
 
     val length = BufferUtils.getUnsignedInt(b)
diff --git a/core/src/test/scala/com/nutomic/ensichat/core/header/ContentHeaderTest.scala b/core/src/test/scala/com/nutomic/ensichat/core/header/ContentHeaderTest.scala
index bb94cd3..9717959 100644
--- a/core/src/test/scala/com/nutomic/ensichat/core/header/ContentHeaderTest.scala
+++ b/core/src/test/scala/com/nutomic/ensichat/core/header/ContentHeaderTest.scala
@@ -10,16 +10,16 @@ import org.junit.Assert._
 object ContentHeaderTest {
 
   val h1 = new ContentHeader(AddressTest.a1, AddressTest.a2, 1234,
-    Text.Type, Some(123), Some(new GregorianCalendar(1970, 1, 1).getTime), 5)
+    Text.Type, Some(123), Some(new GregorianCalendar(1970, 1, 1).getTime), 3)
 
   val h2 = new ContentHeader(AddressTest.a1, AddressTest.a3,
-    30000, Text.Type, Some(8765), Some(new GregorianCalendar(2014, 6, 10).getTime), 20)
+    30000, Text.Type, Some(8765), Some(new GregorianCalendar(2014, 6, 10).getTime), 2)
 
   val h3 = new ContentHeader(AddressTest.a4, AddressTest.a2,
-    250, Text.Type, Some(77), Some(new GregorianCalendar(2020, 11, 11).getTime), 123)
+    250, Text.Type, Some(77), Some(new GregorianCalendar(2020, 11, 11).getTime), 1)
 
   val h4 = new ContentHeader(Address.Null, Address.Broadcast,
-    ContentHeader.SeqNumRange.last, 0, Some(0xffff), Some(new Date(0L)), 0xff)
+    ContentHeader.SeqNumRange.last, 0, Some(0xffff), Some(new Date(0L)), 6)
 
   val h5 = new ContentHeader(Address.Broadcast, Address.Null,
     0, 0xff, Some(0), Some(new Date(0xffffffffL)), 0)
diff --git a/core/src/test/scala/com/nutomic/ensichat/core/header/MessageHeaderTest.scala b/core/src/test/scala/com/nutomic/ensichat/core/header/MessageHeaderTest.scala
index e1c660b..8cf0e48 100644
--- a/core/src/test/scala/com/nutomic/ensichat/core/header/MessageHeaderTest.scala
+++ b/core/src/test/scala/com/nutomic/ensichat/core/header/MessageHeaderTest.scala
@@ -7,11 +7,11 @@ import org.junit.Assert._
 
 object MessageHeaderTest {
 
-  val h1 = new MessageHeader(ContentHeader.ContentMessageType, AddressTest.a1, AddressTest.a2, 1234,
+  val h1 = new MessageHeader(ContentHeader.ContentMessageType, AddressTest.a1, AddressTest.a2, 3,
     0)
 
   val h2 = new MessageHeader(ContentHeader.ContentMessageType, Address.Null, Address.Broadcast,
-    ContentHeader.SeqNumRange.last, 0xff, 3)
+    ContentHeader.SeqNumRange.last, 6, 3)
 
   val h3 = new MessageHeader(ContentHeader.ContentMessageType, Address.Broadcast, Address.Null, 0, 3)