diff --git a/ext/mbstring/tests/GHSA-wm6j-2649-pv75.phpt b/ext/mbstring/tests/GHSA-wm6j-2649-pv75.phpt
new file mode 100644
index 000000000000..5451b17a89be
--- /dev/null
+++ b/ext/mbstring/tests/GHSA-wm6j-2649-pv75.phpt
@@ -0,0 +1,32 @@
+--TEST--
+GHSA-wm6j-2649-pv75
+--EXTENSIONS--
+mbstring
+--SKIPIF--
+<?php
+if (!function_exists('mb_regex_encoding')) die('skip mb_regex_encoding() not available');
+?>
+--FILE--
+<?php
+try {
+	mb_regex_encoding('iso-8859-11');
+} catch (ValueError $v) {
+	var_dump($v->getMessage());
+}
+$test_str = 'x';
+
+if (mb_ereg_search_init($test_str)) {
+    $val = mb_ereg_search_pos("x");
+    var_dump($val);
+} else {
+    var_dump(false);
+}
+?>
+--EXPECTF--
+string(%d) "mb_regex_encoding(): Argument #1 ($encoding) must be a valid encoding, "iso-8859-11" given"
+array(2) {
+  [0]=>
+  int(0)
+  [1]=>
+  int(1)
+}