diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c
index 5a52c856..3ae94780 100644
--- a/ip/ipmaddr.c
+++ b/ip/ipmaddr.c
@@ -128,8 +128,10 @@ void read_igmp(struct ma_info **result_p)
 	if (!fp)
 		return;
 	memset(&m, 0, sizeof(m));
-	if (!fgets(buf, sizeof(buf), fp))
+	if (!fgets(buf, sizeof(buf), fp)) {
+		fclose(fp);
 		return;
+	}
 
 	m.addr.family = AF_INET;
 	m.addr.bitlen = 32;