diff --git a/Misc/NEWS b/Misc/NEWS
index cd166702228..31c4a8a6c82 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -200,6 +200,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #17051: Fix a memory leak in os.path.isdir() on Windows. Patch by
+  Robert Xiao.
+
 - Issue #9290: In IDLE the sys.std* streams now implement io.TextIOBase
   interface and support all mandatory methods and properties.
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index d2742a0ee15..776c7c6fb66 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -4229,6 +4229,7 @@ posix__isdir(PyObject *self, PyObject *args)
         return NULL;
 
     attributes = GetFileAttributesA(path);
+    PyMem_Free(path);
     if (attributes == INVALID_FILE_ATTRIBUTES)
         Py_RETURN_FALSE;