CVE-2026-77520

Deferred Deferred - Pending Action

MaxKB Application Information Disclosure via Workflow

Publication date: 2026-09-21

Last updated on: 2026-09-21

Assigner: GitHub, Inc.

Description

MaxKB is an open-source AI assistant for enterprise. In 2.10.2-lts and earlier, a normal user in the same workspace can obtain another user's application_id from the homepage application question-ranking endpoint when the published victim application has ranking activity in the selected date range and the attacker knows or guesses its name, even though direct application detail and debug-open routes deny access. An attacker who can create and publish a workflow application can place the disclosed identifier in an attacker-owned workflow application-node, trigger that workflow, receive output generated by the victim application, and create durable application_chat and application_chat_record rows under the victim application because save and runtime paths do not verify permission to use the referenced application. No fixed version is available as of this review.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-21

Last Modified

2026-09-21

Generated

2026-09-22

AI Q&A

2026-09-22

EPSS Evaluated

N/A

NVD

CVE-2026-77520

Affected Vendors & Products

Vendor	Product	Version / Range
maxkb	maxkb	to 2.10.2-lts (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-862	The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

Attack-Flow Graph

Executive Summary

This vulnerability exists in MaxKB versions 2.10.2-lts and earlier. A normal user in the same workspace can obtain another user's application_id from the homepage application question-ranking endpoint if the victim's application has ranking activity in a selected date range and the attacker knows or guesses its name. The attacker can then create a workflow application, place the disclosed identifier in an attacker-owned workflow application-node, trigger the workflow, and receive output generated by the victim application. This happens because save and runtime paths do not verify permission to use the referenced application.

Detection Guidance

The vulnerability involves unauthorized access to application_id through the application question-ranking endpoint. Monitor logs for unusual requests to this endpoint, especially those referencing unknown or suspicious application names. Check for unexpected creation of application_chat and application_chat_record rows under applications not owned by the requesting user.

Impact Analysis

An attacker could gain unauthorized access to another user's application data, including creating durable application_chat and application_chat_record rows under the victim's application. This could lead to data leakage, unauthorized modifications, or misuse of the victim's application functionality.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, which may violate GDPR's data protection principles or HIPAA's privacy and security rules. Organizations using MaxKB must address this to maintain compliance with these regulations.

Mitigation Strategies

Upgrade to a patched version of MaxKB if available. If no patch exists, restrict access to the application question-ranking endpoint and review all published applications for unauthorized workflow integrations. Implement strict permission checks for application_id usage and application_chat record creation.

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