CVE-2026-79917: MaxKB: Chat share-link endpoint missing owner check: a chat token can publish another user's conversation

Vulnerability summary

CVE-2026-79917 is a medium (CVSS 6.5) Improper Authorization vulnerability in 1panel-dev maxkb. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 19% of scored vulnerabilities.

Timeline

1. 21-09-2026
   PublishedVulnerability first disclosed.
2. 22-09-2026
   Last modifiedVulnerability information updated.

Description

MaxKB is an open-source AI assistant for enterprise. In 2.7.0 through 2.10.4-lts, POST /chat/api/{application_id}/chat/{chat_id}/share_chat verifies that a conversation exists but does not verify that it belongs to the authenticated chat_user_id or to the application bound to the caller's token. An attacker with any chat token and a known victim chat_id can create an unauthenticated public ChatShareLink exposing the victim's conversation and can create PublicFileAccess state that makes associated files retrievable without credentials, with no available revoke path. No fixed version is available as of this review.

• CWE-285Improper AuthorizationThe product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.
• CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.