diff --git a/UPGRADING b/UPGRADING
index 6300cfbdf1734..0025999d80455 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -34,6 +34,12 @@ PHP 8.4 UPGRADE NOTES
     This is no longer the case as a consequence of the bugfixes for GH-12192,
     GH-12208, #55098.
 
+- SPL:
+  . Out of bounds accesses in SplFixedArray now throw an exception of type
+    OutOfBoundsException instead of RuntimeException. As OutOfBoundsException
+    is a child class of RuntimeException, code that uses RuntimeException
+    continues to function.
+
 - Standard:
   . round() now validates the value of the $mode parameter and throws a ValueError
     for invalid modes. Previously invalid modes would have been interpreted as
diff --git a/ext/spl/spl_fixedarray.c b/ext/spl/spl_fixedarray.c
index 95ab191b77824..04330caf83a8c 100644
--- a/ext/spl/spl_fixedarray.c
+++ b/ext/spl/spl_fixedarray.c
@@ -376,8 +376,7 @@ static zval *spl_fixedarray_object_read_dimension_helper(spl_fixedarray_object *
 	}
 
 	if (index < 0 || index >= intern->array.size) {
-		// TODO Change error message and use OutOfBound SPL Exception?
-		zend_throw_exception(spl_ce_RuntimeException, "Index invalid or out of range", 0);
+		zend_throw_exception(spl_ce_OutOfBoundsException, "Index invalid or out of range", 0);
 		return NULL;
 	} else {
 		return &intern->array.elements[index];
@@ -425,8 +424,7 @@ static void spl_fixedarray_object_write_dimension_helper(spl_fixedarray_object *
 	}
 
 	if (index < 0 || index >= intern->array.size) {
-		// TODO Change error message and use OutOfBound SPL Exception?
-		zend_throw_exception(spl_ce_RuntimeException, "Index invalid or out of range", 0);
+		zend_throw_exception(spl_ce_OutOfBoundsException, "Index invalid or out of range", 0);
 		return;
 	} else {
 		/* Fix #81429 */
@@ -465,8 +463,7 @@ static void spl_fixedarray_object_unset_dimension_helper(spl_fixedarray_object *
 	}
 
 	if (index < 0 || index >= intern->array.size) {
-		// TODO Change error message and use OutOfBound SPL Exception?
-		zend_throw_exception(spl_ce_RuntimeException, "Index invalid or out of range", 0);
+		zend_throw_exception(spl_ce_OutOfBoundsException, "Index invalid or out of range", 0);
 		return;
 	} else {
 		zval_ptr_dtor(&(intern->array.elements[index]));
diff --git a/ext/spl/tests/fixedarray_001.phpt b/ext/spl/tests/fixedarray_001.phpt
index 0683555934d53..802a9b8f8b806 100644
--- a/ext/spl/tests/fixedarray_001.phpt
+++ b/ext/spl/tests/fixedarray_001.phpt
@@ -45,9 +45,9 @@ $a[0] = "valueNew";
 var_dump($b[0]);
 ?>
 --EXPECT--
-RuntimeException: Index invalid or out of range
+OutOfBoundsException: Index invalid or out of range
 TypeError: Cannot access offset of type string on SplFixedArray
-RuntimeException: Index invalid or out of range
+OutOfBoundsException: Index invalid or out of range
 string(6) "value0"
 string(6) "value2"
 string(6) "value3"
diff --git a/ext/spl/tests/fixedarray_002.phpt b/ext/spl/tests/fixedarray_002.phpt
index 0ee2dcb8ba11d..329fa57eacb16 100644
--- a/ext/spl/tests/fixedarray_002.phpt
+++ b/ext/spl/tests/fixedarray_002.phpt
@@ -69,11 +69,11 @@ var_dump(count($a), $a->getSize(), count($a) == $a->getSize());
 ?>
 --EXPECT--
 A::offsetSet
-RuntimeException: Index invalid or out of range
+OutOfBoundsException: Index invalid or out of range
 A::offsetGet
 TypeError: Cannot access offset of type string on SplFixedArray
 A::offsetUnset
-RuntimeException: Index invalid or out of range
+OutOfBoundsException: Index invalid or out of range
 A::offsetSet
 A::offsetSet
 A::offsetSet