fix: bump authkit-js to ^0.20.1 and harden returnTo redirects

[devin-ai-integration]

Summary

Automated first-pass security fix for SEC-1300. Requires human security review before merge.

authkit-react exact-pinned @workos-inc/authkit-js to 0.20.0, freezing every consumer on a version with two confirmed defects that were fixed upstream in 0.20.1 (commit 138b602, PR #122):

1. Logout-allowlist bypass → open redirect / javascript: XSS. In 0.20.0, signOut({ returnTo }) for a logged-out user (no access token in memory) calls window.location.assign(returnTo) on the raw, unvalidated value — bypassing the WorkOS logout-redirect allowlist that devs reasonably assume always validates returnTo.
2. Auth-bootstrap DoS via malformed state. In 0.20.0, the callback handler does JSON.parse(stateParam) unguarded; a crafted link (?code=x&state=%7Bnot-json) throws, which — combined with the provider having no .catch() — permanently wedges the app on isLoading: true for that navigation.

Both were reproduced against the real 0.20.0 bundle and confirmed rejected on 0.20.1 (see Linear ticket for full attacker-perspective PoC).

Changes

• package.json / lockfile: "@workos-inc/authkit-js": "0.20.0" → "^0.20.1". The caret both delivers the fixes and lets future patches flow instead of re-freezing consumers.

• src/provider.tsx: add a .catch() to the createClient() promise so an init failure settles into an unauthenticated state instead of wedging isLoading: true (defense-in-depth for the DoS):

     }).then(async (client) => {
       ...
       setState((prev) => ({ ...prev, isLoading: false, user }));
  -  });
  +  }).catch((error) => {
  +    console.error(error);
  +    setState((prev) => ({ ...prev, isLoading: false, user: null }));
  +  });

• README.md: the onRedirectCallback example previously taught window.location.href = state.returnTo with no validation (seeding open-redirect/XSS into consumer apps). Now validates state.returnTo is same-origin before navigating, plus a security note that state is untrusted URL input.

Testing

• npm run build — success.
• npm run format:check — clean.
• Reproduced the signOut open-redirect + javascript: XSS and the state DoS against the built 0.20.0 bundle (real browser + jsdom); verified 0.20.1 throws NoSessionError / treats malformed state as absent.

This is an automated first-pass fix; a human security reviewer should confirm before merge.

Link to Devin session: https://app.devin.ai/sessions/5de3ea20d3ad44aa81cb15e4b4da448a

[devin-ai-integration]

Original prompt from Linear User

Please work on ticket "authkit-react hard-pins authkit-js 0.20.0, shipping the known-fixed unvalidated signOut({ returnTo }) redirect (logout-allowlist bypass enabling XSS/open redirect) plus an auth-callback state parse DoS to all consumers" (SEC-1300)

@playbook:playbook-b588614117c7477a9b9729928385384f

[devin-ai-integration]

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[linear-code]

SEC-1300

[greptile-apps]

Greptile Summary

This PR upgrades the authentication client and hardens initialization and redirect handling.

• Upgrades @workos-inc/authkit-js from 0.20.0 to ^0.20.1.
• Prevents superseded client initialization promises from updating provider state.
• Settles initialization failures into an unauthenticated state.
• Documents same-origin validation for callback redirects.

Confidence Score: 5/5

This looks safe to merge.

• The cleanup guard covers both successful and failed stale initializations.
• No blocking issue remains in the updated code.

Important Files Changed

Filename	Overview
src/provider.tsx	Guards promise settlement after cleanup and handles client initialization failures.
package.json	Updates the authentication client dependency to the patched release range.
package-lock.json	Locks the authentication client to version 0.20.1.
README.md	Adds same-origin redirect validation and warns that callback state is untrusted.

_{Reviews (2): Last reviewed commit: "fix: ignore stale createClient results a..." | Re-trigger Greptile}