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fix(proxy): strip malformed Next-Router-State-Tree headers #70

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Merged
mattdjenkinson merged 1 commit into from
Apr 8, 2026
Merged

fix(proxy): strip malformed Next-Router-State-Tree headers #70

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19 changes: 19 additions & 0 deletions apps/login/src/proxy.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,25 @@ export async function proxy(request: NextRequest) {
// Add the original URL as a header to all requests
const requestHeaders = new Headers(request.headers);

// Strip malformed Next-Router-State-Tree headers to prevent Next.js from
// throwing "The router state header was sent but could not be parsed."
// This happens when stale clients (pre-deployment) send incomplete router state.
const routerStateHeader = requestHeaders.get("Next-Router-State-Tree");
if (routerStateHeader) {
let isValid = false;
try {
const parsed = JSON.parse(decodeURIComponent(routerStateHeader));
isValid = Array.isArray(parsed) && parsed.length >= 2;
} catch {
isValid = false;
}
if (!isValid) {
requestHeaders.delete("Next-Router-State-Tree");
requestHeaders.delete("Rsc");
requestHeaders.delete("Next-Router-Prefetch");
}
}

// Extract "organization" search param from the URL and set it as a header if available
const organization = request.nextUrl.searchParams.get("organization");
if (organization) {
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