diff --git a/lib/pure/asynchttpserver.nim b/lib/pure/asynchttpserver.nim
index 9b369c4bc7..93afc770f0 100644
--- a/lib/pure/asynchttpserver.nim
+++ b/lib/pure/asynchttpserver.nim
@@ -152,7 +152,7 @@ proc parseProtocol(protocol: string): tuple[orig: string, major, minor: int] =
         protocol)
   result.orig = protocol
   i.inc protocol.parseSaturatedNatural(result.major, i)
-  i.inc # Skip .
+  if i < protocol.len: inc i # Skip .
   i.inc protocol.parseSaturatedNatural(result.minor, i)
 
 proc sendStatus(client: AsyncSocket, status: string): Future[void] =