# Flask — CWE-407 Diamond Traversal Scan: CLEAN

Scanned: 2026-03-30

## Files examined

- `src/flask/views.py` — `MethodView.__init_subclass__` iterates `cls.__bases__` but does NOT recurse; one-level only
- `src/flask/sansio/app.py` — `exc_class.__mro__` iteration (linear, no recursion)
- `src/flask/blueprints.py` — no class hierarchy traversal

## Result

No diamond recursion defects found. Flask does not perform recursive `__bases__` traversal.
The `__init_subclass__` hook in `MethodView` iterates one level of `__bases__` to collect
HTTP method names — this is O(B) where B is the number of direct bases, not recursive.