CVE-2026-56321 in Capgo
Summary
by MITRE • 06/23/2026
Capgo (backend Supabase edge functions) before 12.128.2 does not apply the global authentication middleware to the GET /private/role_bindings/:org_id endpoint, unlike the POST and DELETE role_bindings routes, so unauthenticated requests reach the handler instead of being rejected at the middleware layer. The handler still performs its own authorization check and returns Unauthorized, so no direct data exposure occurs; the flaw is inconsistent authentication enforcement across HTTP methods that could enable authorization bypass if the handler logic changes.
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Analysis
by VulDB Data Team • 06/23/2026
The vulnerability in Capgo's backend infrastructure resides within the Supabase edge functions implementation where inconsistent authentication enforcement creates a potential authorization bypass vector. This issue affects versions prior to 12.128.2 and specifically targets the GET /private/role_bindings/:org_id endpoint which fails to apply the global authentication middleware that is correctly implemented for POST and DELETE operations on the same resource. The fundamental flaw lies in the differential treatment of HTTP methods where the GET request bypasses the middleware layer entirely while other methods properly enforce authentication checks.
The technical implementation reveals a clear violation of consistent security controls where the authentication middleware operates as a gatekeeper for some but not all HTTP methods accessing the same resource endpoint. This inconsistency creates a scenario where unauthenticated requests can reach the handler function directly, bypassing the initial authentication layer that should reject unauthorized access attempts before they reach business logic. The handler itself contains its own authorization checks that would subsequently return Unauthorized responses, but this defensive programming approach is insufficient as it relies on the proper implementation of all security controls rather than enforcing them at the appropriate architectural layer.
From an operational perspective this vulnerability represents a critical inconsistency in access control enforcement that could enable attackers to exploit timing windows or logic flaws if the handler implementation changes in future updates. The flaw demonstrates poor adherence to security by design principles where authentication should be enforced consistently across all methods of accessing protected resources. This inconsistency creates potential attack surface expansion and violates the principle of least privilege by allowing potentially unauthorized access paths to exist even when the system ultimately enforces proper authorization checks.
The vulnerability aligns with CWE-693, which addresses protection mechanism failures, and reflects poor implementation of access control mechanisms where authentication enforcement is not consistently applied across all HTTP methods. This pattern also maps to ATT&CK technique T1078.004 which covers legitimate credentials and the use of compromised accounts, as inconsistent authentication enforcement could allow attackers to bypass initial access controls through different method paths. The security impact extends beyond immediate unauthorized access attempts to potential future exploitation if the underlying handler logic is modified without considering all possible entry points.
Mitigation strategies should focus on enforcing consistent authentication middleware application across all HTTP methods for the same resource endpoint, ensuring that no method can bypass the global authentication layer. Organizations should implement comprehensive testing procedures to validate that all HTTP methods for protected endpoints consistently apply security controls and conduct regular audits of middleware enforcement patterns. The fix requires ensuring that the GET /private/role_bindings/:org_id endpoint properly applies the global authentication middleware just as POST and DELETE operations do, thereby establishing consistent access control enforcement across all request methods for the same resource.
The vulnerability demonstrates a classic case of incomplete security implementation where defensive measures are selectively applied rather than comprehensively enforced. This approach creates potential attack vectors through method-specific bypasses that could prove particularly problematic if system logic changes or if attackers discover additional entry points that were not initially considered. Security teams should prioritize the immediate patching of this inconsistency and implement monitoring for similar patterns across other endpoints to prevent future occurrences of differential authentication enforcement.
The root cause analysis reveals a fundamental architectural issue in how access control is implemented within the Supabase edge functions environment where middleware configuration does not maintain consistent application across all HTTP methods. This represents a failure in security architecture design that should be addressed through comprehensive policy enforcement and regular security reviews of all endpoint access controls, ensuring that authentication mechanisms are applied uniformly regardless of the HTTP method or request path utilized by attackers.