CVE-2026-85619 in AppFlowy-Cloud
Summary
by MITRE • 09/04/2026
AppFlowy-Cloud 0.9.64 fails to verify that requested collab objects belong to the workspace in authorization checks, allowing attackers to access documents and database rows across workspaces. Attackers can supply a victim's object ID with their own workspace ID to bypass access controls and read, modify, or delete cross-workspace data.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 09/04/2026
The vulnerability identified in AppFlowy-Cloud version 0.9.64 represents a critical failure in server-side authorization logic, specifically within the collaborative editing subsystem that manages document synchronization across multiple workspaces. This flaw stems from an improper verification of object ownership relative to the authenticated user's context. When a client application requests access to or modification of specific collaboration objects, such as documents or database rows, the backend service fails to rigorously validate that the requested resource identifier is legitimately associated with the workspace ID provided in the request header or payload. This architectural oversight creates a direct path for insecure direct object references, allowing an authenticated attacker to manipulate API parameters to access resources outside their designated boundaries.
From a technical perspective, the core issue lies in the absence of cross-referencing checks between the resource identifier and the user's workspace membership list during the authorization phase. In secure implementations, every request involving a specific data entity must be validated against an access control matrix that confirms both the validity of the object ID and its association with the authenticated session's scope. By omitting this verification step, the application treats any validly formatted object ID as accessible if it is paired with a workspace ID controlled by the attacker. This allows for horizontal privilege escalation where data intended to be isolated within one organizational unit becomes exposed to another through simple parameter tampering on the client side or via direct API manipulation tools.
The operational impact of this vulnerability is severe, encompassing unauthorized access to sensitive business intelligence, intellectual property, and personal user data stored across different workspaces. An attacker can read confidential documents, extract structured database rows containing potentially personally identifiable information, modify critical project configurations, or delete essential records entirely. This lack of isolation undermines the fundamental security model of multi-tenant collaboration platforms, where workspace boundaries are intended to serve as strict containment zones for data privacy and compliance purposes. The ability to traverse these boundaries effectively breaks the principle of least privilege, granting users access far beyond their assigned permissions without requiring additional authentication or exploitation of other system flaws.
This vulnerability aligns with CWE-284, which describes Improper Access Control, specifically highlighting failures in authorization checks that allow unauthorized access to resources. Furthermore, it maps directly to MITRE ATT&CK technique T1078, Valid Accounts, as the attack relies on legitimate credentials but abuses them through parameter manipulation rather than credential theft or brute force methods. The specific behavior of accessing objects across different organizational units also reflects aspects of CWE-639, Authorization Bypass Through User-Controlled Key, where the attacker controls a key (the workspace ID) that is used to determine access rights without sufficient validation against other contextual factors like object ownership.
Mitigation strategies must prioritize immediate patching to version 0.9.65 or later, which addresses this authorization logic flaw by enforcing strict binding between resource identifiers and their parent workspaces during every API call. In the interim, administrators should implement robust input validation at the application gateway level to ensure that object IDs are verified against a whitelist of resources associated with each user's active sessions. Additionally, adopting a defense-in-depth approach involves enabling comprehensive audit logging for all data access events related to collaboration objects, allowing security teams to detect anomalous patterns indicative of cross-workspace traversal attempts. Regular penetration testing focusing on horizontal privilege escalation scenarios is also recommended to identify similar logic flaws in other modules before they can be exploited by malicious actors seeking to exfiltrate or corrupt organizational data.