# BadRequest: The CSRF token is missing.

- **ID:** `python/flask-csrf-protection-error`
- **Domain:** python
- **Category:** auth_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

启用了 CSRF 保护，但请求中未包含有效的 CSRF 令牌。

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **** (100% success)
   ```
   <form method="post">
    <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
</form>
   ```

## Dead Ends

- **** — 会降低安全性，容易遭受 CSRF 攻击 (70% fail)
- **** — 令牌会过期，且不安全 (90% fail)