diff -ruN postgresql-7.4.5-old/src/pl/plpgsql/src/gram.y postgresql-7.4.5/src/pl/plpgsql/src/gram.y
--- postgresql-7.4.5-old/src/pl/plpgsql/src/gram.y	2003-10-30 18:18:55.000000000 +0100
+++ postgresql-7.4.5/src/pl/plpgsql/src/gram.y	2005-02-10 13:24:10.871958168 +0100
@@ -512,6 +512,10 @@
 					{
 						int i = $1->nfields++;
 
+						/* Guard against overflowing the array on malicious input */
+						if (i >= 1024)
+							yyerror("too many parameters specified for refcursor");
+
 						$1->fieldnames[i] = $3->refname;
 						$1->varnos[i] = $3->varno;