Attack Chain

1. An authenticated attacker gains access to a legitimate user account within the vulnerable Onlook application.
2. The attacker identifies tRPC API procedures susceptible to broken object level authorization, specifically project.get, member.remove, and chat.conversation.delete.
3. The attacker intercepts or crafts API requests for these target procedures.
4. The attacker replaces the legitimate UUIDs (e.g., projectId, conversationId) in the request parameters with arbitrary UUIDs belonging to other users or resources they do not own.
5. The Onlook application processes these requests without performing adequate authorization checks to verify if the authenticated user has legitimate access to the supplied arbitrary UUID.
6. The application performs the requested action (read, modify, delete) on the resources associated with the arbitrary UUID, effectively bypassing object-level authorization.
7. The attacker successfully reads other users' project data, removes members from projects, or deletes other users' chat conversation histories, achieving unauthorized data access, manipulation, or destruction.

Impact

Successful exploitation of CVE-2026-65013 allows authenticated attackers to fully compromise the privacy and integrity of other users' data within the Onlook platform. Attackers can gain complete unauthorized access to sensitive project data, modify or delete critical information, and disrupt collaboration by removing project members. Furthermore, they can delete entire conversation histories, leading to significant data loss and potential compliance issues. While specific victim counts are not available, all users of Onlook versions 0.2.32 and earlier are at risk, with potential consequences including reputational damage, financial losses due to data breaches, and a complete loss of trust in the platform's security.

Recommendation

• Patch CVE-2026-65013 by updating Onlook to a version beyond 0.2.32, specifically incorporating the fix from commit 423e2e9, immediately.
• Implement API gateway logging and monitoring to detect unusual patterns in tRPC API calls, such as repeated attempts to access various projectId or conversationId values by a single user, specifically for procedures like project.get, member.remove, and chat.conversation.delete.
• Review application-level logs for signs of unauthorized data access, modification, or deletion linked to arbitrary UUID values.