The PraisonAI Platform's POST /workspaces/{workspace_id}/members endpoint is protected only by a minimal role check (default min_role="member") but does not verify if the caller has permission to assign roles. It directly passes the user_id and role from the request body to MemberService.add without additional permission checks. This flaw enables any user with basic membership privileges to add any user, including attacker-controlled accounts, as workspace owners, resulting in privilege escalation and cross-tenant member injection. The vulnerability affects all versions prior to 0.1.4, which includes the fix.

An attacker with the lowest workspace privilege can escalate their privileges to owner by adding arbitrary users with owner roles. This leads to full control over the workspace, potentially compromising confidentiality and integrity of workspace data and operations. The vulnerability does not affect availability. The CVSS 3.1 score is 9.6 (critical), reflecting network attack vector, low attack complexity, low privileges required, no user interaction, scope change, and high confidentiality and integrity impact.

Upgrade PraisonAI Platform to version 0.1.4 or later, where this privilege escalation vulnerability is patched. No other mitigation or temporary workaround is indicated in the available data.