[Automated] Draft docs (agentgateway): csrf: treat Origin: null as a cross-origin request (+1 related)

assets/agw-docs/pages/security/csrf.md

@@ -8,6 +8,10 @@ According to [OWASP](https://community.owasp.org/attacks/csrf), CSRF is defined
 
 To help prevent CSRF attacks, you can enable CSRF protection for your gateway or a specific route. For each route that you apply the CSRF policy to, the filter checks to make sure that a request's origin matches its destination. If the origin and destination do not match, a 403 Forbidden error code is returned. 
 
+{{< version exclude-if="1.6.x,1.5.x,1.4.x,1.3.x,1.2.x,1.1.x,1.0.x" >}}
+For requests without a `Sec-Fetch-Site` header, the policy compares the host and port in the `Origin` header with the request `Host` header. The policy ignores the scheme, so the origin `https://www.example.com` matches a plain HTTP request to `www.example.com`. The policy treats an `Origin: null` header as a cross-origin request, and rejects it unless `additionalOrigins` contains `null`.
+{{< /version >}}
+
 Review the following diagram to see an example CSRF request flow:
 ```mermaid
 sequenceDiagram
@@ -74,7 +78,7 @@ Configure an {{< reuse "agw-docs/snippets/policy.md" >}} to enable CSRF protecti
    | Field | Description | 
    |-------|-------------|
    | `csrf` | Enables CSRF protection for the targeted Gateway or routes. When configured, all cross-origin requests are validated. | 
-   | `additionalOrigins` | List of additional origins that are allowed to make requests to your app beyond the same-origin requests. This is useful for trusted partners, subdomains, or CDNs. Origins cannot include wildcards. | 
+   | `additionalOrigins` | List of additional origins that are allowed to make requests to your app beyond the same-origin requests. This is useful for trusted partners, subdomains, or CDNs. Origins cannot include wildcards.{{< version exclude-if="1.6.x,1.5.x,1.4.x,1.3.x,1.2.x,1.1.x,1.0.x" >}} To allow requests that send an `Origin: null` header, add `null` to this list.{{< /version >}} |
 
 
 {{< doc-test paths="csrf" >}}

content/docs/standalone/main/documentation/configuration/security/csrf.md

@@ -24,6 +24,8 @@ According to [OWASP](https://community.owasp.org/attacks/csrf), CSRF is defined
 
 To help prevent CSRF attacks, the CSRF policy implements a multi-layered validation approach to allow or block requests based on their properties. The policy checks that the request's origin matches its destination. If the origin and destination do not match, a 403 Forbidden error code is returned. Unlike CORS, CSRF protection works with all HTTP clients, not just browsers.
 
+For requests without a `Sec-Fetch-Site` header, the policy compares the host and port in the `Origin` header with the request `Host` header. The policy ignores the scheme, so the origin `https://www.example.com` matches a plain HTTP request to `www.example.com`. The policy treats an `Origin: null` header as a cross-origin request, and rejects it unless `additionalOrigins` contains `null`.
+
 Review the following diagram to see an example CSRF request flow:
 ```mermaid
 sequenceDiagram
@@ -59,7 +61,7 @@ sequenceDiagram
 Allowed requests are as follows.
 
 - Safe methods (`GET`, `HEAD`, `OPTIONS`) from any origin
-- Same-origin requests (`Origin` matches `Host`)
+- Same-origin requests, where the host and port in `Origin` match `Host`, regardless of scheme
 - Requests from origins in `additionalOrigins`
 - Requests with `Sec-Fetch-Site: same-origin` or `Sec-Fetch-Site: none`
 
@@ -69,6 +71,7 @@ Blocked requests, which receive a `403 Forbidden` response with the message "CSR
 
 - Cross-site requests with `Sec-Fetch-Site: cross-site` (unless trusted)
 - Cross-site requests where `Origin` doesn't match `Host` (unless trusted)
+- Requests without `Sec-Fetch-Site` and with `Origin: null` (unless trusted)
 - Malformed `Origin` headers in cross-site contexts
 
 > [!NOTE]
@@ -158,7 +161,7 @@ agentgateway -f config-mcp.yaml --validate-only
 {{< /doc-test >}}
 
 The `additionalOrigins` setting is a list of trusted origins allowed to make cross-site requests.
-- Format: `"scheme://host[:port]"`
+- Format: `"scheme://host[:port]"`. To allow requests that send an `Origin: null` header, add `"null"`.
 - Examples: `"https://www.example.com"`, `"http://localhost:3000"`
 
 For strict CSRF protection to prevent all cross-site requests, set `additionalOrigins` to an empty list, as shown in the following route-level policy.