diff --git a/usr.bin/elfctl/elfctl.c b/usr.bin/elfctl/elfctl.c
--- a/usr.bin/elfctl/elfctl.c
+++ b/usr.bin/elfctl/elfctl.c
@@ -41,6 +41,7 @@
 #include <getopt.h>
 #include <libelf.h>
 #include <stdbool.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -249,13 +250,13 @@
 		if (i == len) {
 			if (isdigit(feature[0])) {
 				char *eptr;
-				long val;
+				unsigned long long val;
 
 				errno = 0;
-				val = strtol(feature, &eptr, 0);
+				val = strtoll(feature, &eptr, 0);
 				if (eptr == feature || *eptr != '\0')
 					errno = EINVAL;
-				else if (val > UINT_MAX)
+				else if (val > UINT32_MAX)
 					errno = ERANGE;
 				if (errno != 0) {
 					warn("%s invalid", feature);