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Graph/cross-origin-cookie-access-mismatch

Pattern

Cross-Subdomain Cookie Reachability

cross-origin-cookie-access-mismatch

Cookies set for one host (e.g., api subdomain or specific JSESSIONID) fail to be sent or read on other origins because Domain, SameSite, and httpOnly constraints aren’t aligned, breaking auth and even websocket/proxy flows.

Node Details

Public graph metadata

Updated7/7/2026

Connections

30 linked nodes

Cookie “__vercel_live_token” has been rejected because it is in a cross-site context and its “SameSite” is “Lax” or “Strict” — deployed it on Vercel. Tension: But i setup cookies in my project like this. Outcome: Then you need to use https://localhost:5000 and not http://localhost:5000.

When the UI calls the `POST /auth/callback/passkey` endpoint. Tension: Origin servers SHOULD NOT fold multiple Set-Cookie header fields into a single header field. Outcome: Cloudflare seem to be in the wrong here.

when I refresh my page the cookie gets deleted — I have deployed my sveltekit frontend and python flask backend on vercel. Tension: On localhost, they worked just fine however when I deployed it, the cookies were not persistent. Outcome: it does sets the cookie, but on refresh, the cookie gets disappeared.

requests with the forbidden fields sailed through to the write path. Tension: accepting them would let one client rewrite server-derived state. Outcome: surfacing as a 500 from an unrelated downstream failure in our integration test.

Using Fetch from my `index.html` from my `portal.mydomain.com` does not. — Enter `api.mydomain.com` into a browser directly does save my cookie. Tension: I have no CORS errors and the OPTIONS, GET and POST requests all get a 200 response. Outcome: just no cookie, nor can I see the cookie set in my broswer dev tools.

RedirectResponse goes to "/" without the authentication cookie

AADSTS9002325: Proof Key for Code Exchange is required for cross-origin authorization code redemption. Tension: redirects uris not matching.

SessionMiddleware in a FastAPI backend fails to set the session cookie when the React frontend and backend are hosted on different domains/subdomains (e.g., XXX-ui.fly.dev vs XXX-api.fly.dev). The browser rejects the cookie with an 'invalid domain' error and no session is maintained.

were not accessible in js and in browser — Cookies are being set and sent with the next request. Outcome: The problem solved by adding `domain="blueberry.adefe.xyz"` to the cookie in response.

MissingKeyMissing Key-Pair-Id query parameter or cookie value — {urn}/manifest/{derivativeurn}/signedcookies. Tension: I get the following error that suggest I'm missing a header.

Embedding a CPQ web app as an iframe inside Salesforce fails to persist authentication cookies/session for API calls. Login in a new tab isn’t recognized inside the Salesforce iframe, preventing authorized requests.

the cookie will be specifically set with `domain=app.sunsetland.com.au`. Tension: if we were to host another subdomain aside from `app.`, we actually would likely encounter the reCAPTCHA challenge again.

can I create, from 2. and 3. a server side httpOnly cookie (containing a `widget_id`) of domain `mycompany-example.com`, that can be used during step 5. Outcome: when the user visits our website so we know which widget they come from ?

Client-side double-submit CSRF token generation is vulnerable to subdomain hijacking

Confusion about cookie authentication versus token authentication

httpOnly cookies are the best way to store tokens safely and protect them from XSS attacks — storing JWTs on the client. Tension: JavaScript won't be allowed to read httpOnly cookies. How would the client handle routes authentication? Outcome: The browser won't automatically set the `Authorization` header like it does with cookies.

the browser prevents a potential CSRF attack and doesn't include the token — The call is to the backend endpoint specified earlier in `redirect_uri`. Tension: I need a browser to include the `ASP.NET_SessionId` cookie in the request. Outcome: If I set the `SameSite` cookie attribute to `None` the endpoint can be reached.

Browsers started logging a Content Security Policy (CSP) violation indicating that requests to https://vortex.data.microsoft.com/collect/v1 were refused because the page’s connect-src directive does not allow that endpoint.

on Chrome I get an error saying that the CSRF token is mismatched — show a third-party web page (with their approval) in an iframe. Tension: This site has a different domain to my parent site. Outcome: The site displays fine on firefox.

If I check 'Remember Me' in form, this add a cookie with name "REMEMBERME". Tension: I'm implementing custom authenticator. Outcome: your cookie is normal.

The session identifier (req.sessionID) changed on every subsequent HTTP request from the React client to the Express server, preventing consistent session persistence.

Accessing https://example.com results in a “too many redirects” loop, while other domain variants redirect correctly for a React app served by Apache with Cloudflare-managed DNS/SSL.

req.cookies.jwt is defined in localhost but undefined in deployment — The cookies are being set in the browser. Tension: the only problem is I can't access them. Outcome: Here to ken is undefined.

one is working without any credential or cookie[SessionId] but another one is not working — two api's in my spring mvc project which have identical structure. Tension: while calling using Postman or while hitting the APIs in browser/UI project.

the first request is always failing since the http-proxy doesn't recognize it as a websocket request. Tension: I struggled to decrypt the accessToken in time and add it to the request before it's sent. Outcome: for now it's not bothering me that much.

Requests to the Django/DRF backend fail with “CSRF Failed: Origin checking failed - http://localhost:8000/ does not match any trusted origins.”

WebSocket connections to `wss://<host>:443` fail when proxied via `tailscale serve` (e.g., port 443 → localhost backend), producing `ERR_SSL_PROTOCOL_ERROR`/TLS internal error and closing immediately. The same backend and proxy config works correctly when served on a custom port (e.g., 8443).

Wget before 1.21.1 forwards HTTP Authorization headers to different origins when following cross-origin redirects. — when following cross-origin redirects. Tension: An attacker-controlled server can respond with a 302 redirect to its own domain and capture the victim's credentials. Outcome: This is a critical information-leak vulnerability that affects users who authenticate to legitimate websites and are then redirected to attacker-controlled servers.

curl will accept and store the super-cookie — In lib/cookie.c, Curl_cookie_add() guards against setting cookies whose Domain attribute is a Public Suffix. Tension: libpsl's matching is case-sensitive against its lowercase PSL data. Outcome: the PSL test never sees the canonical 'co.uk'.

throws "Cookies can only be modified in a Server Action or Route Handler" — called from Next.js 15 Server Components (pages, layouts). Tension: The error appears intermittently — only when the session needs refreshing (controlled by `updateAge` config). Outcome: With `updateAge: 300` (5 minutes), it crashes every ~5 minutes for active users.

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