Description

Onyx is an open-source AI platform. Prior to 4.3.0, Onyx Enterprise Edition's PATCH /manage/admin/user-group/{user_group_id} and POST /manage/admin/user-group/{user_group_id}/add-users endpoints in ee/onyx/server/user_group/api.py call update_user_group and add_users_to_user_group in ee/onyx/db/user_group.py without enforcing _validate_curator_can_modify_group, allowing a curator to add accounts to arbitrary groups and obtain document access through get_acl_for_user and the OpenSearch access_control_list filter. This issue is fixed in version 4.3.0.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-08-17T22:17:16.130Z",
  "pubdate": "2026-08-17T22:17:16.130Z",
  "executiveSummary": "An authorization bypass vulnerability exists in Onyx Enterprise Edition prior to version 4.3.0, specifically within the user group management endpoints.\nThe vulnerability class involves missing access control checks, allowing authenticated users with curator privileges to modify arbitrary user groups.\nThe affected systems include Onyx Enterprise Edition deployments running versions prior to 4.3.0, exposing administrative functions through inadequate validation.\nThe risk implications involve privilege escalation and unauthorized data access, as attackers can manipulate group memberships to gain access to restricted corporate knowledge bases and documents.\nAttacker capabilities include the ability to interact with specific administrative API endpoints and assign user accounts to arbitrary groups without possessing the necessary administrative authorization.\nExploitation requires authenticated access to the Onyx platform with at least curator-level privileges, enabling the abuse of improperly secured backend database operations.",
  "technicalDetails": "The root cause of the vulnerability stems from inadequate function-level access control within the backend implementation of the Onyx Enterprise Edition administrative API.\nSpecifically, the endpoints PATCH /manage/admin/user-group/{user_group_id} and POST /manage/admin/user-group/{user_group_id}/add-users defined in ee/onyx/server/user_group/api.py invoke the database manipulation functions update_user_group and add_users_to_user_group located in ee/onyx/db/user_group.py.\nDuring this process, the application fails to invoke the critical security validation function _validate_curator_can_modify_group, which is intended to restrict curators from modifying groups outside their permitted scope.\nThe vulnerable components comprise the administrative routing layer and the underlying database access layer responsible for user group management in Onyx Enterprise Edition prior to version 4.3.0.\nAuthentication and privilege requirements dictate that the attacker must possess valid credentials with curator privileges, yet the missing authorization check allows them to exceed their intended boundary limits.\nThe attack flow proceeds as follows: an authenticated actor with curator privileges sends a crafted HTTP PATCH or POST request targeting the vulnerable user group endpoints with a specified user_group_id.\nBecause the server-side code omits the execution of _validate_curator_can_modify_group, the database layer blindly processes the request, successfully adding arbitrary user accounts to protected or restricted user groups.\nFollowing this successful exploitation, the post-exploitation impact is manifested through the application's access control list (ACL) evaluation mechanism.\nBy manipulating group memberships, the attacker forces get_acl_for_user and the OpenSearch access_control_list filter to grant the newly added accounts unauthorized document access privileges, violating data segmentation and confidentiality boundaries."
}