--- src/cmd/ksh93/edit/edit.c
+++ src/cmd/ksh93/edit/edit.c	2007-09-16 23:57:45.000000000 +0200
@@ -1478,8 +1478,14 @@
 		nv_unset(ED_CHRNOD);
 	else
 	{
-		strncpy(inbuff,cp,bufsize);
-		insize = strlen(inbuff);
+		if (bufsize>0)
+		{
+			strncpy(inbuff,cp,bufsize);
+			inbuff[bufsize-1]='\0';
+			insize = strlen(inbuff);
+		}
+		else
+			insize=0;
 	}
 	nv_unset(ED_TXTNOD);
 	return(insize);