diff --git a/src/inet.c b/src/inet.c
index 4b630f53..cd774968 100644
--- a/src/inet.c
+++ b/src/inet.c
@@ -130,7 +130,7 @@ static int inet_ntop6(const unsigned char *src, char *dst, size_t size) {
       tp += strlen(tp);
       break;
     }
-    tp += sprintf(tp, "%x", words[i]);
+    tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);
   }
   /* Was it a trailing run of 0x00's? */
   if (best.base != -1 && (best.base + best.len) == ARRAY_SIZE(words))