diff --git a/lib/libjail/jail.c b/lib/libjail/jail.c
--- a/lib/libjail/jail.c
+++ b/lib/libjail/jail.c
@@ -737,6 +737,12 @@
 	int i, nval, ival;
 	char valbuf[INET6_ADDRSTRLEN];
 
+	if (jp->jp_value == NULL) {
+		snprintf(jail_errmsg, JAIL_ERRMSGLEN,
+		    "parameter %s was not imported", jp->jp_name);
+		errno = EINVAL;
+		return (NULL);
+	}
 	if ((jp->jp_ctltype & CTLTYPE) == CTLTYPE_STRING) {
 		value = strdup(jp->jp_value);
 		if (value == NULL)