diff --git a/src/pipewire/conf.c b/src/pipewire/conf.c
index f6dd56847..34091031b 100644
--- a/src/pipewire/conf.c
+++ b/src/pipewire/conf.c
@@ -358,8 +358,9 @@ int pw_conf_save_state(const char *prefix, const char *name, const struct pw_pro
 	if ((sfd = open_write_dir(path, sizeof(path), prefix)) < 0)
 		return sfd;
 
-	tmp_name = alloca(strlen(name)+5);
-	sprintf(tmp_name, "%s.tmp", name);
+	size_t tmp_name_size = strlen(name) + 5;
+	tmp_name = alloca(tmp_name_size);
+	snprintf(tmp_name, tmp_name_size, "%s.tmp", name);
 	if ((fd = openat(sfd, tmp_name,  O_CLOEXEC | O_CREAT | O_WRONLY | O_TRUNC, 0600)) < 0) {
 		res = -errno;
 		pw_log_error("can't open file '%s': %m", tmp_name);