--- a/sys/dev/raid/vinum/vinumio.c
+++ b/sys/dev/raid/vinum/vinumio.c
@@ -795,7 +795,9 @@
 	    for (cptr = config_text; *cptr != '\0';) {    /* love this style(9) */
 		volatile int parse_status;		    /* return value from parse_config */
 
-		for (eptr = config_line; (*cptr != '\n') && (*cptr != '\0');) /* until the end of the line */
+		for (eptr = config_line;			    /* until the end of the line, */
+		(*cptr != '\n') && (*cptr != '\0')		    /* but never write past the */
+		&& (eptr < &config_line[MAXCONFIGLINE * 2 - 1]);) /* end of config_line */
 		    *eptr++ = *cptr++;
 		*eptr = '\0';				    /* and delimit */
 		if (setjmp(command_fail) == 0) {	    /* come back here on error and continue */