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Luu, T.J.

GHSA-qgvm-j2hm-6m38: Flowise: Unauthenticated OAuth2 token refresh endpoint returns access tokens — enables token theft for any connected service

criticalvulnerability

security

Source: GitHub Advisory DatabaseAugust 4, 2026CVE-2026-70478

Summary

Flowise has a security flaw where an unauthenticated endpoint (`POST /api/v1/oauth2-credential/refresh/:credentialId`) can refresh OAuth2 tokens (credentials that allow apps to act on behalf of a user) without requiring login. An attacker who knows a credential ID can call this endpoint to get a fresh access token and use it to impersonate the victim on connected services like Google or Microsoft.

Solution / Mitigation

Remove the refresh endpoint from `WHITELIST_URLS` in `packages/server/src/utils/constants.ts` and add an authentication check to the route handler in `packages/server/src/routes/oauth2/index.ts` to require login before allowing token refresh.