diff --git a/lib/libc/stdio/vfprintf.c b/lib/libc/stdio/vfprintf.c
index 105d7fec6fea..4abdbc4e7d28 100644
--- a/lib/libc/stdio/vfprintf.c
+++ b/lib/libc/stdio/vfprintf.c
@@ -39,7 +39,7 @@
 static char sccsid[] = "@(#)vfprintf.c	8.1 (Berkeley) 6/4/93";
 #endif
 static const char rcsid[] =
-		"$Id: vfprintf.c,v 1.12 1997/02/22 15:02:40 peter Exp $";
+		"$Id: vfprintf.c,v 1.13 1997/12/19 21:59:22 bde Exp $";
 #endif /* LIBC_SCCS and not lint */
 
 /*
@@ -643,14 +643,18 @@ fp_begin:		if (prec == -1)
 			break;
 #endif /* FLOATING_POINT */
 		case 'n':
+			n = ret;
+			if ((fp->_flags & __SSTR) &&
+			    fp->_bf._size < n)
+				n = fp->_bf._size;
 			if (flags & QUADINT)
-				*GETARG(quad_t *) = ret;
+				*GETARG(quad_t *) = n;
 			else if (flags & LONGINT)
-				*GETARG(long *) = ret;
+				*GETARG(long *) = n;
 			else if (flags & SHORTINT)
-				*GETARG(short *) = ret;
+				*GETARG(short *) = n;
 			else
-				*GETARG(int *) = ret;
+				*GETARG(int *) = n;
 			continue;	/* no output */
 		case 'O':
 			flags |= LONGINT;