CVE-2026-67329 in better-auth
Summary
by MITRE • 08/01/2026
@better-auth/stripe versions >= 1.4.11 and < 1.6.21, and >= 1.7.0-beta.0 and < 1.7.0-beta.10, contain an authorization bypass in organization subscription actions. The middleware validates the organization ID taken from the request query string against the authorizeReference callback, but the handler reads the organization ID only from the request body and falls back to the caller's active organization from their session. When these differ, an authenticated member of multiple organizations can perform subscription actions (cancel, change plan, restore, billing portal access) against an organization they belong to but should not manage, and can access another organization's billing details including payment methods, invoices, and subscription state.
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Analysis
by VulDB Data Team • 08/01/2026
This vulnerability represents a critical authorization bypass affecting the @better-auth/stripe package across specific version ranges, demonstrating a fundamental flaw in access control validation mechanisms. The issue stems from inconsistent organization ID handling between middleware validation and actual handler execution, creating a security gap that allows authenticated users to perform unauthorized subscription management actions against organizations they do not administrate. The vulnerability operates through a sophisticated bypass pattern where the middleware component correctly validates the organization ID from the query string against authorization callbacks, yet the subsequent handler logic retrieves the organization ID exclusively from the request body and defaults to the user's active session organization when this field is absent or mismatched.
The technical flaw manifests as a classic inconsistency in parameter validation where the system performs authorization checks on one data source while executing operations on another, creating a dangerous divergence in access control decisions. This pattern aligns with CWE-284, which describes inadequate access control mechanisms that allow unauthorized users to gain privileges or access resources they should not be permitted to reach. The vulnerability enables attackers to manipulate subscription lifecycle operations including cancellation, plan changes, and restoration actions against organizations they belong to but lack administrative rights for, while simultaneously granting access to sensitive billing information such as payment methods, invoices, and subscription states that belong to other organizations.
The operational impact of this authorization bypass extends beyond simple privilege escalation to encompass comprehensive data exposure and service manipulation capabilities. An authenticated member of multiple organizations can exploit this vulnerability to perform subscription management activities against any organization they are affiliated with but should not administrate, effectively allowing them to disrupt billing operations or gain unauthorized access to financial information. The exposure of billing details including payment methods, invoices, and subscription states creates significant risk for both the affected organizations and their customers, potentially enabling fraud, data theft, or service disruption. This vulnerability directly violates principles outlined in the ATT&CK framework under privilege escalation and credential access tactics, where attackers can leverage legitimate authentication to access unauthorized resources.
Mitigation strategies should focus on implementing consistent organization ID validation throughout the entire request processing pipeline, ensuring that all authorization checks operate on the same data source and that fallback mechanisms do not introduce security gaps. Organizations should immediately upgrade to patched versions of @better-auth/stripe, specifically those beyond 1.6.21 or 1.7.0-beta.10, while implementing additional monitoring for unauthorized subscription management activities. The fix must ensure that middleware validation and handler execution operate on identical organization ID sources, eliminating the possibility of session-based fallbacks that could bypass authorization checks. Security teams should also conduct comprehensive audits of similar patterns in their codebase to identify potential instances where parameter validation inconsistencies might create similar vulnerabilities, particularly focusing on multi-tenant applications where users may belong to multiple organizations with varying access levels.