diff --git a/xserver/os/io.c b/xserver/os/io.c
index 26f9161ef..83986af92 100644
--- a/xserver/os/io.c
+++ b/xserver/os/io.c
@@ -395,6 +395,8 @@ ReadRequestFromClient(ClientPtr client)
                     needed = get_big_req_len(request, client);
             }
             client->req_len = needed;
+            if (needed > MAXINT >> 2)
+                return -(BadLength);
             needed <<= 2;
         }
         if (gotnow < needed) {