diff --git a/src/standard.c b/src/standard.c
index f4f8b2a..75a0389 100644
--- a/src/standard.c
+++ b/src/standard.c
@@ -2038,10 +2038,11 @@
 char *human_time(int t, short hz_div) {
 	static char rv[sizeof("24855d23h")+1];	// longest of "23h59m" and "59m59s"
 	char *p = rv;
+	char *end = rv + sizeof(rv);
 	int cnt=2;				// print two numbers
 
 	if (unlikely(t < 0 || hz_div <= 0)) {
-		sprintf(p, "?");
+		snprintf(p, end - p, "?");
 		return rv;
 	}
 
@@ -2049,22 +2050,22 @@
 		t /= hz_div;
 
 	if (t >= DAY) {
-		p += sprintf(p, "%dd", t / DAY);
+		p += snprintf(p, end - p, "%dd", t / DAY);
 		cnt--;
 	}
 
 	if (cnt && t % DAY / HOUR) {
-		p += sprintf(p, "%dh", t % DAY / HOUR);
+		p += snprintf(p, end - p, "%dh", t % DAY / HOUR);
 		cnt--;
 	}
 
 	if (cnt && t % HOUR / MINUTE) {
-		p += sprintf(p, "%dm", t % HOUR / MINUTE);
+		p += snprintf(p, end - p, "%dm", t % HOUR / MINUTE);
 		cnt--;
 	}
 
 	if ((cnt && t % MINUTE) || !t)					// also display '0s'
-		p += sprintf(p, "%ds", t % MINUTE / SEC);
+		p += snprintf(p, end - p, "%ds", t % MINUTE / SEC);
 
 	return rv;
 }