diff --git a/sys/dev/apple/smc/smc_sysctl.c b/sys/dev/apple/smc/smc_sysctl.c
--- a/sys/dev/apple/smc/smc_sysctl.c
+++ b/sys/dev/apple/smc/smc_sysctl.c
@@ -48,7 +48,7 @@
 int
 apple_smc_mb_sysctl_fanid(SYSCTL_HANDLER_ARGS)
 {
-	uint8_t buf[16];
+	uint8_t buf[16] = { 0 };
 	device_t dev = (device_t)arg1;
 	int fan = arg2;
 	char *desc;