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fix(backend): Prevent excessive handshakes #6635

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Merged
merged 2 commits into from
Aug 26, 2025
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fix(backend): Prevent excessive handshakes #6635

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b73afbf
prevent handshake from triggering twice when a dev browser is present…
brkalow Aug 25, 2025
db961af
fix test
brkalow Aug 25, 2025
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5 changes: 5 additions & 0 deletions .changeset/grumpy-groups-run.md
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Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
---
'@clerk/backend': patch
---

Fixes an issue where a handshake would trigger more than intended in development.
2 changes: 1 addition & 1 deletion integration/tests/handshake.test.ts
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Expand Up @@ -1437,7 +1437,7 @@ test.describe('Client handshake with an organization activation avoids infinite
// Critical cookie: __clerk_redirect_count
headers.set(
'Cookie',
`${devBrowserCookie} __client_uat=${claims.iat}; __session=${token}; __clerk_redirect_count=1`,
`${devBrowserCookie} __client_uat=${claims.iat}; __session=${token}; __clerk_redirect_count=3`,
);

const res = await fetch(thisApp.serverUrl + '/organizations-by-id/org_a', {
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3 changes: 2 additions & 1 deletion packages/backend/src/tokens/handshake.ts
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Expand Up @@ -222,6 +222,7 @@ export class HandshakeService {
const newUrl = new URL(this.authenticateContext.clerkUrl);
newUrl.searchParams.delete(constants.QueryParameters.Handshake);
newUrl.searchParams.delete(constants.QueryParameters.HandshakeHelp);
newUrl.searchParams.delete(constants.QueryParameters.DevBrowser);
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@nikosdouvlis nikosdouvlis Aug 26, 2025

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This looks good to me. Was there any reason we used to delete it from the clerk-js side only or just an omission?

headers.append(constants.Headers.Location, newUrl.toString());
headers.set(constants.Headers.CacheControl, 'no-store');
}
Expand Down Expand Up @@ -323,7 +324,7 @@ ${developmentError.getFullMessage()}`,

const newCounterValue = this.authenticateContext.handshakeRedirectLoopCounter + 1;
const cookieName = constants.Cookies.RedirectCount;
headers.append('Set-Cookie', `${cookieName}=${newCounterValue}; SameSite=Lax; HttpOnly; Max-Age=3`);
headers.append('Set-Cookie', `${cookieName}=${newCounterValue}; SameSite=Lax; HttpOnly; Max-Age=2`);
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@brkalow brkalow Aug 25, 2025

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3 was an arbitrary choice here, I'm reducing to 2 to mitigate the case where someone switches between orgs quickly when using org url sync

return false;
}

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2 changes: 1 addition & 1 deletion packages/backend/src/tokens/request.ts
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Expand Up @@ -386,7 +386,7 @@ export const authenticateRequest: AuthenticateRequest = (async (
if (!mustActivate) {
return null;
}
if (authenticateContext.handshakeRedirectLoopCounter > 0) {
if (authenticateContext.handshakeRedirectLoopCounter >= 3) {
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@brkalow brkalow Aug 25, 2025

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Again, reducing the case where someone might be switching quickly. this should help, in addition to the max-age change, reduce false-positives of redirect loop detection

// We have an organization that needs to be activated, but this isn't our first time redirecting.
// This is because we attempted to activate the organization previously, but the organization
// must not have been valid (either not found, or not valid for this user), and gave us back
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