CVE-2026-62861 in Typebot
Summary
by MITRE • 08/26/2026
TypeBot is a chatbot builder tool. Prior to 3.18.0, any authenticated non-guest workspace member can remove another workspace's public custom domain and make typebots on that domain unavailable. The custom-domain delete handler in handleDeleteCustomDomain.ts authorizes a caller against a client-supplied workspaceId but sends the client-supplied domain name to the shared Vercel project before verifying that the domain belongs to that workspace. This issue is fixed in version 3.18.0.
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified in TypeBot versions prior to 3.18.0 represents a critical authorization flaw rooted in improper verification of access controls for sensitive administrative actions. Specifically, the defect resides within the custom domain deletion handler located in the file handleDeleteCustomDomain.ts. This component is responsible for managing public-facing DNS configurations that link user-defined domains to their chatbot instances. The core technical failure involves an order-of-operations error where the system authorizes the caller against a client-supplied workspace identifier but fails to validate that the specific domain being targeted actually belongs to that authorized workspace before proceeding with the deletion request sent to the shared Vercel project infrastructure.
In practical operational terms, this logic gap allows any authenticated user who holds non-guest privileges within a TypeBot workspace to execute destructive actions against domains associated with other workspaces. By manipulating the client-supplied domain name parameter while maintaining their own valid workspaceId for authentication checks, an attacker can bypass intended isolation boundaries. The system accepts the request because the initial authorization check passes based on the user's membership in one workspace, yet it proceeds to delete a custom domain belonging to a completely different organization or project. This lack of cross-resource validation means that access control decisions are not properly scoped to the specific resource being modified.
The impact of this vulnerability is severe and directly affects service availability and business continuity for affected organizations. Since TypeBot relies on these public custom domains to serve chatbot interfaces, removing a domain renders all typebots hosted under that domain inaccessible to end-users. This constitutes a denial-of-service condition triggered by an authenticated actor with relatively low privileges. Beyond the immediate disruption of user-facing services, this action can cause significant reputational damage and operational downtime for businesses relying on TypeBot for customer engagement or support workflows. The ability to arbitrarily remove domains also suggests potential risks related to data integrity if associated configurations are permanently lost without recovery mechanisms.
From a classification perspective, this vulnerability aligns with CWE-269, which describes Improper Privilege Control, specifically where an actor obtains privileges that they should not have for the specific resource in question. It also maps closely to CWE-862, Missing Authorization, as the application fails to enforce proper access controls on a protected object (the custom domain). In terms of adversary tactics, this behavior is consistent with MITRE ATT&CK technique T1499, Endpoint Denial of Service, or more broadly T1078, Valid Accounts, where an attacker leverages legitimate credentials to disrupt service availability. The flaw exemplifies a common pattern in web application development known as insecure direct object references when combined with insufficient server-side validation of resource ownership during state-changing operations.
To mitigate this vulnerability and prevent similar issues in future developments, it is imperative that all administrative endpoints implement strict authorization checks that verify the relationship between the authenticated user's workspace context and the target resource. Developers must ensure that before any destructive action such as domain deletion is executed against an external service like Vercel, the backend explicitly confirms that the requested domain ID or name is legitimately owned by the workspace associated with the requesting user's session token. This validation should occur prior to constructing and sending the API request to downstream infrastructure. Additionally, implementing comprehensive logging for all custom domain modifications can aid in forensic analysis if such an incident occurs. Organizations using TypeBot versions earlier than 3.18.0 are strongly advised to upgrade immediately to the patched version where this logic error has been corrected by enforcing proper ownership verification before processing deletion requests.