diff --git a/ext/date/php_date.c b/ext/date/php_date.c
index 0e24e4450641..690713eeb5e5 100644
--- a/ext/date/php_date.c
+++ b/ext/date/php_date.c
@@ -4733,7 +4733,7 @@ static void php_date_interval_initialize_from_hash(php_interval_obj *intobj, con
 	PHP_DATE_INTERVAL_READ_PROPERTY("s", s, timelib_sll, -1)
 	{
 		const zval *z_arg = zend_hash_str_find(myht, "f", sizeof("f") - 1);
-		if (z_arg) {
+		if (z_arg && Z_TYPE_P(z_arg) <= IS_STRING) {
 			intobj->diff->us = zend_dval_to_lval(zval_get_double(z_arg) * 1000000.0);
 		}
 	}
@@ -4749,7 +4749,7 @@ static void php_date_interval_initialize_from_hash(php_interval_obj *intobj, con
 	{
 		const zval *z_arg = zend_hash_str_find(myht, "civil_or_wall", sizeof("civil_or_wall") - 1);
 		intobj->civil_or_wall = PHP_DATE_CIVIL;
-		if (z_arg) {
+		if (z_arg && Z_TYPE_P(z_arg) <= IS_STRING) {
 			zend_long val = zval_get_long(z_arg);
 			intobj->civil_or_wall = val;
 		}
diff --git a/ext/date/tests/date_interval_wakeup_declared_property.phpt b/ext/date/tests/date_interval_wakeup_declared_property.phpt
new file mode 100644
index 000000000000..5478c2ef7ae8
--- /dev/null
+++ b/ext/date/tests/date_interval_wakeup_declared_property.phpt
@@ -0,0 +1,41 @@
+--TEST--
+DateInterval::__wakeup() must not pass raw property-table zvals to zval_get_double()/zval_get_long()
+--FILE--
+<?php
+error_reporting(E_ALL & ~E_DEPRECATED);
+
+/* date_object_get_properties_interval() returns the object's raw property table
+ * when the interval is not initialized. Declared properties are IS_INDIRECT in
+ * that table, which the conversion helpers do not accept. */
+
+class DeclaredInitialized extends DateInterval { public float $f = 1.5; }
+class DeclaredUninitialized extends DateInterval { public float $f; }
+class DeclaredCivilOrWall extends DateInterval { public int $civil_or_wall = 1; }
+#[AllowDynamicProperties] class Dynamic extends DateInterval {}
+
+foreach (['DeclaredInitialized', 'DeclaredUninitialized', 'DeclaredCivilOrWall'] as $cls) {
+    $o = (new ReflectionClass($cls))->newInstanceWithoutConstructor();
+    $o->__wakeup();
+    echo $cls, ": ok\n";
+}
+
+/* A dynamic property is a plain zval, so it is still read normally. */
+$o = (new ReflectionClass('Dynamic'))->newInstanceWithoutConstructor();
+$o->f = 0.25;
+$o->__wakeup();
+echo "Dynamic: ", $o->f, "\n";
+
+/* The normal round-trip is unaffected. */
+$i = new DateInterval('PT1S');
+$i->f = 0.5;
+$restored = unserialize(serialize($i));
+echo "roundtrip f: ", $restored->f, "\n";
+echo "roundtrip s: ", $restored->s, "\n";
+?>
+--EXPECT--
+DeclaredInitialized: ok
+DeclaredUninitialized: ok
+DeclaredCivilOrWall: ok
+Dynamic: 0.25
+roundtrip f: 0.5
+roundtrip s: 1