Dieses Standardverhalten schützt vor einer Klasse von **Cross-Site Request Forgery (CSRF)**-Angriffen in einem sehr spezifischen Szenario.

Diese Angriffe nutzen aus, dass Browser Skripte Requests senden lassen, ohne einen CORS-Preflight-Check durchzuführen, wenn sie:

* keinen `Content-Type`-Header haben (z. B. mit `fetch()` und einem `Blob`-Body)
* und keine Authentifizierungsdaten senden.

Diese Art von Angriff ist vor allem relevant, wenn:

Esses ataques exploram o fato de que navegadores permitem que scripts enviem requisições sem fazer qualquer verificação de preflight de CORS quando:

- não têm um cabeçalho `Content-Type` (por exemplo, usando `fetch()` com um corpo `Blob`)
- e não enviam nenhuma credencial de autenticação.

Esse tipo de ataque é relevante principalmente quando:

* `max_age` – Legt eine maximale Zeit in Sekunden fest, die Browser CORS-Responses zwischenspeichern dürfen. Standardmäßig `600`.

Die Middleware antwortet auf zwei besondere Arten von HTTP-Requests ...

### CORS-Preflight-Requests { #cors-preflight-requests }

Dies sind alle `OPTIONS`-Requests mit `Origin`- und `Access-Control-Request-Method`-Headern.

Ces attaques exploitent le fait que les navigateurs permettent à des scripts d’envoyer des requêtes sans effectuer de pré-vérification CORS (preflight) lorsqu’ils :

* n’ont pas d’en-tête `Content-Type` (par ex. en utilisant `fetch()` avec un corps `Blob`)
* et n’envoient aucune information d’authentification.

Ce type d’attaque est surtout pertinent lorsque :

- Kubeadm: Added support during the preflight check "CreateJob" of "kubeadm upgrade" to check if there are no nodes where a Pod can be scheduled. If there are none, show a warning and skip this preflight check. This can happen in single node clusters where the only node was drained. ([#124503](https://github.com/kubernetes/kubernetes/pull/124503), [@neolit123](https:/...

O middleware responde a dois tipos específicos de solicitação HTTP...

### Requisições CORS pré-voo (preflight) { #cors-preflight-requests }

Estas são quaisquer solicitações `OPTIONS` com cabeçalhos `Origin` e `Access-Control-Request-Method`.

## CSRF 위험 { #csrf-risk }

이 기본 동작은 매우 특정한 시나리오에서 **Cross-Site Request Forgery (CSRF)** 공격의 한 유형에 대한 보호를 제공합니다.

이러한 공격은 브라우저가 다음과 같은 경우 CORS 사전 요청(preflight) 검사를 수행하지 않고 스크립트가 요청을 보내도록 허용한다는 점을 악용합니다:

- `Content-Type` 헤더가 없음(예: `Blob` 본문과 함께 `fetch()` 사용)
- 그리고 어떠한 인증 자격 증명도 보내지 않음

이 유형의 공격은 주로 다음과 같은 경우에 관련이 있습니다:

- 애플리케이션이 로컬(예: `localhost`) 또는 내부 네트워크에서 실행 중이고

- Kubeadm: switch the preflight check (called 'Swap') that verifies if swap is enabled on Linux hosts to report a warning instead of an error. This is related to the graduation of the NodeSwap feature gate in the kubelet to Beta and being enabled by default in 1.23 - allows swap support on Linux hosts. In the next release of kubeadm (1.24) the preflight check will be removed, thus we recommend that you stop using it - e.g. via `--ignore-preflight-errors`...

* kubeadm will now pull required images during preflight checks if it cannot find them on the system. ([#64105](https://github.com/kubernetes/kubernetes/pull/64105), [@chuckha](https://github.com/chuckha))

`CORSMiddleware` отвечает на два типа HTTP-запросов...

### CORS-запросы с предварительной проверкой { #cors-preflight-requests }

Это любые `OPTIONS`-запросы с заголовками `Origin` и `Access-Control-Request-Method`.