diff --git a/ext/calendar/gregor.c b/ext/calendar/gregor.c
index 3aef7ae6ac50..eaee9c8c73c7 100644
--- a/ext/calendar/gregor.c
+++ b/ext/calendar/gregor.c
@@ -209,6 +209,7 @@ zend_long GregorianToSdn(
 
 	/* check for invalid dates */
 	if (inputYear == 0 || inputYear < -4714 ||
+		inputYear > INT_MAX - 4800 ||
 		inputMonth <= 0 || inputMonth > 12 ||
 		inputDay <= 0 || inputDay > 31) {
 		return (0);
diff --git a/ext/calendar/julian.c b/ext/calendar/julian.c
index ac580aa08e06..53a207a606f4 100644
--- a/ext/calendar/julian.c
+++ b/ext/calendar/julian.c
@@ -222,6 +222,7 @@ zend_long JulianToSdn(
 
 	/* check for invalid dates */
 	if (inputYear == 0 || inputYear < -4713 ||
+		inputYear > INT_MAX - 4800 ||
 		inputMonth <= 0 || inputMonth > 12 ||
 		inputDay <= 0 || inputDay > 31) {
 		return (0);
diff --git a/ext/calendar/tests/gh22602.phpt b/ext/calendar/tests/gh22602.phpt
new file mode 100644
index 000000000000..d165a0174094
--- /dev/null
+++ b/ext/calendar/tests/gh22602.phpt
@@ -0,0 +1,20 @@
+--TEST--
+Bug GH-22602: (gregoriantojd() and juliantojd() integer overflow with INT_MAX year)
+--EXTENSIONS--
+calendar
+--FILE--
+<?php
+$max = PHP_INT_MAX > 2147483647 ? 2147483647 : PHP_INT_MAX;
+$min = PHP_INT_MAX > 2147483647 ? -2147483648 : PHP_INT_MIN;
+
+var_dump(gregoriantojd(5, 5, $max));
+var_dump(gregoriantojd(5, 5, $min));
+var_dump(juliantojd(5, 5, 2147483647));
+var_dump(juliantojd(5, 5, -2147483647));
+
+?>
+--EXPECT--
+int(0)
+int(0)
+int(0)
+int(0)