From 7459cc6d0aa02d9f75c1291fccc4132efaa4dc67 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 27 Oct 2022 14:12:27 +0900
Subject: [PATCH] Check month range as civil

---
 ext/date/date_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 83d493c..de35e82 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -761,6 +761,8 @@ c_valid_civil_p(int y, int m, int d, double sg,
 
     if (m < 0)
 	m += 13;
+    if (m < 1 || m > 12)
+	return 0;
     if (d < 0) {
 	if (!c_find_ldom(y, m, sg, rjd, ns))
 	    return 0;