diff -up dhcp-4.0.0/common/conflex.c.parse dhcp-4.0.0/common/conflex.c
--- dhcp-4.0.0/common/conflex.c.parse	2008-01-16 15:26:09.000000000 -1000
+++ dhcp-4.0.0/common/conflex.c	2008-01-16 16:02:48.000000000 -1000
@@ -182,8 +182,12 @@ static int get_char (cfile)
 			c = EOF;
 		}
 	} else {
-		c = cfile->inbuf [cfile->bufix];
-		cfile->bufix++;
+		if (strlen(cfile->inbuf) >= (cfile->bufix + 1)) {
+			c = EOF;
+		} else {
+			c = cfile->inbuf [cfile->bufix];
+			cfile->bufix++;
+		}
 	}
 
 	if (!cfile->ugflag) {