CVE-2026-79917: MaxKB: Chat share-link endpoint missing owner check: a chat token can publish another user's conversation
MaxKB is an open-source AI assistant for enterprise. In 2.7.0 through 2.10.4-lts, POST /chat/api/{applicationid}/chat/{chatid}/sharechat verifies that a conversation exists but does not verify that it belongs to the authenticated chatuserid or to the application bound to the caller's token. An attacker with any chat token and a known victim chatid 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.
Affected Software
Event History
Frequently Asked Questions
Who is exposed to this issue?
Deployments running MaxKB versions 2.7.0 through 2.10.4-lts are affected. Exploitation requires an attacker to possess any valid chat token and know a victim conversation's chat_id.
What can an attacker do with a victim chat ID?
The attacker can call the share endpoint to create an unauthenticated public share link for the victim's conversation. Associated files may also become retrievable without credentials through PublicFileAccess state.
Does the attacker need to be the conversation owner or use a token for the same application?
No. The endpoint checks that the conversation exists but does not verify ownership against the authenticated chat_user_id or verify that the conversation belongs to the application associated with the caller's token.
Can exposure be revoked after a malicious share link is created?
The available information states that there is no revoke path for the created public file access state. No fixed MaxKB version was available as of the review.