diff --git a/lib/modules/Protocols.pmod/HTTP.pmod/Query.pike b/lib/modules/Protocols.pmod/HTTP.pmod/Query.pike
index e163d890c50c08287ebe31b2cb097e6f341c650d..6bf2af7dafdfbadc022433829468ed030e88982d 100644
--- a/lib/modules/Protocols.pmod/HTTP.pmod/Query.pike
+++ b/lib/modules/Protocols.pmod/HTTP.pmod/Query.pike
@@ -579,7 +579,7 @@ string data()
        buf += con->read(l);
    }
    if(zero_type( len ))
-     len = sizeof( data ) - datapos - 1;
+     len = sizeof( buf ) - datapos - 1;
 #ifdef HTTP_QUERY_NOISE
    werror("buf[datapos..]     : %O\n", buf[datapos
 				       ..min(sizeof(buf), datapos+19)]);