5.3.0: Proxy should not rewrite the Origin header for non WS requests  #17562

Describe the bug

Originally reported on PR #16558 (comment)

This has broken my app's proxying behavior for the reasons you suspected above.

I am not using WS but I need my host header rewritten without my origin header rewritten, or else my CI fails.

Origin vs. Host Headers: The Key Difference

Host:

Tells the server which website/application is being requested.
Used for virtual hosting (multiple sites on one IP address).
Modified by the proxy when changeOrigin: true to match the target backend.

Origin:

Indicates the origin (protocol, domain, port) where the request initiated.
Primarily used for Cross-Origin Resource Sharing (CORS) security.
Not typically modified by proxies, even with changeOrigin: true. This is a browser security mechanism.

This change seems to leave the proxying open to CSRF attacks.

Perhaps it is wanted in a WS context, but I need a way to turn off the origin reassignment.

I'd prefer to have two options (as mentioned above) if you really need to maintain this behavior... rewriteHost and rewriteOrigin, with a warning on the latter

Reproduction

Not available

Steps to reproduce

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System Info

Not available

Used Package Manager

npm

Logs

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