CVE-2026-70478: Flowise unauthenticated OAuth2 token refresh in credential endpoint

Executive brief

Flowise, an open-source tool for building LLM applications, contains a security flaw in how it handles third-party service connections like Google, Microsoft, and GitHub. An unauthorized attacker can remotely request a new access token for these connected services without providing any credentials. If successful, this allows the attacker to take over the victim's connected accounts and access their private data.

Technical details

The OAuth2 token refresh endpoint (POST /api/v1/oauth2-credential/refresh/:credentialId) was incorrectly included in the WHITELIST_URLS constant, bypassing authentication requirements. When called with a valid credential ID, the server decrypts the stored OAuth2 credentials, performs a refresh request to the provider, and returns the resulting access_token directly in the JSON response. Attackers can obtain credential IDs through enumeration or other information leaks to gain full access to a victim's connected third-party accounts. This vulnerability is patched in version 3.1.3.

Affected products

• FlowiseAI flowise <= 3.1.2

Timeline

• 2026-07-29: disclosed
• 2026-08-04: advisory
• 2026-08-04: patched

References

• https://api.github.com/users/DeathsPirate
• https://github.com/DeathsPirate
• https://api.github.com/users/DeathsPirate/gists%7B/gist_id%7D
• https://api.github.com/users/DeathsPirate/repos
• https://avatars.githubusercontent.com/u/6913191?v=4
• https://api.github.com/users/DeathsPirate/events%7B/privacy%7D