Executive brief
Flowise is an open-source platform for building AI agents visually. A broken access control flaw in its payment source endpoint allows any authenticated user to retrieve sensitive billing and profile information (email addresses, account balances, payment methods) belonging to other customers by manipulating a customer ID parameter. This exposure could lead to identity theft, account takeover, and regulatory violations under data protection laws like GDPR.
Technical details
The vulnerability is a broken access control (CWE-639) flaw at the GET /api/v1/organization/customer-default-source endpoint. While the endpoint enforces authentication (requires a valid session token), it fails to verify object-level authorization—it does not check whether the requesting user owns or has permission to access the requested customerId. An authenticated attacker can craft requests with customer IDs in a predictable Stripe-formatted pattern (cus_XXXX) to enumerate and retrieve PII and financial data. The attack requires only network access and a valid account; no additional user interaction is needed. The vulnerability was patched in version 3.1.3 by implementing proper ownership validation on the customerId parameter, as shown in commit 4d7899d02ca370a5510406be5c91483085a412f9.
Affected products
- FlowiseAI Flowise prior to 3.1.3
Timeline
- 2026-07-27: disclosed
- 2026-06-25: patched: Fix released in version 3.1.3
- 2026-08-04: advisory
References
- https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-2364-jh4q-m9vm
- https://github.com/FlowiseAI/Flowise/pull/6321
- https://github.com/FlowiseAI/Flowise/commit/4d7899d02ca370a5510406be5c91483085a412f9
- https://github.com/FlowiseAI/Flowise
- https://github.com/FlowiseAI/Flowise/releases/tag/flowise%403.1.3