diff --git a/beacon_chain/ssz/bytes_reader.nim b/beacon_chain/ssz/bytes_reader.nim
index b314a8eba..71ff38cc0 100644
--- a/beacon_chain/ssz/bytes_reader.nim
+++ b/beacon_chain/ssz/bytes_reader.nim
@@ -169,6 +169,8 @@ func readSszValue*(input: openarray[byte], T: type): T =
           raise newException(MalformedSszError, "SSZ field offsets are not monotonically increasing")
         elif endOffset > input.len:
           raise newException(MalformedSszError, "SSZ field offset points past the end of the input")
+        elif startOffset < boundingOffsets[0]:
+          raise newException(MalformedSszError, "SSZ field offset points outside bounding offsets")
 
       # TODO The extra type escaping here is a work-around for a Nim issue:
       when type(FieldType) is type(SszType):