diff --git a/Misc/NEWS.d/next/Library/2026-06-20-15-18-46.gh-issue-151763.t-jCFF.rst b/Misc/NEWS.d/next/Library/2026-06-20-15-18-46.gh-issue-151763.t-jCFF.rst
new file mode 100644
index 00000000000000..8e0ee35dfb412e
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-06-20-15-18-46.gh-issue-151763.t-jCFF.rst
@@ -0,0 +1,4 @@
+Fix a possible NULL dereference in ``os.path.normpath()`` for bytes paths
+when memory allocation fails. The function now correctly propagates
+``MemoryError`` instead of passing a NULL object to
+``PyUnicode_EncodeFSDefault()``.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 1f1b7fa729c01c..c52d2e7d5bfbd9 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -6145,6 +6145,9 @@ os__path_normpath_impl(PyObject *module, path_t *path)
     else {
         result = PyUnicode_FromWideChar(norm_path, norm_len);
     }
+    if (result == NULL) {
+        return NULL;
+    }
     if (PyBytes_Check(path->object)) {
         Py_SETREF(result, PyUnicode_EncodeFSDefault(result));
     }