CVE-2026-77366
Received Received - Intake

Obsidian-tc Vault Access Bypass via JWT Misconfiguration

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: GitHub, Inc.

Description
obsidian-tc is a governed, agent-ready Model Context Protocol server for Obsidian vaults. Prior to 1.3.1, tool dispatch does not compare the caller-controlled input.vault value with the vault bound to the caller, the JSON Web Token (JWT) has no vault claim, and the folder access-control list is shared globally. Any valid token can therefore select another configured vault and read, write, or delete its contents through affected tools. Version 1.3.1 fixes the vulnerability by binding tokens and request context to a vault and rejecting mismatched input.vault values before scope checks.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-13
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-77366
EUVD
EUVD-2026-97737

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
The-40-Thieves obsidian-tc < 1.3.1

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-639 The 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.
CWE-863 The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

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Executive Summary

This vulnerability in obsidian-tc before version 1.3.1 allows any valid HTTP bearer token to access, modify, or delete any configured vault by passing its ID as a tool argument. The issue occurs because tokens lack a vault claim in their JWT and the folder access-control list is global, enabling cross-vault access without proper authorization checks.

Detection Guidance

To detect this vulnerability, check if your obsidian-tc instance is running a version prior to 1.3.1. Use commands like 'npm list obsidian-tc' or inspect the version in your deployment logs. Monitor for unauthorized vault access attempts in logs where input.vault mismatches the caller's bound vault.

Impact Analysis

An attacker with a valid token could read sensitive data, alter files, or delete entire vaults across multiple tenants. This could lead to data breaches, loss of intellectual property, or service disruption, especially in multi-tenant environments where vaults are isolated for security.

Compliance Impact

This vulnerability likely violates compliance requirements for data isolation and access controls in GDPR and HIPAA. Unauthorized cross-vault access could expose protected health information or personal data, leading to legal penalties, fines, or reputational damage due to non-compliance with data protection regulations.

Mitigation Strategies

Upgrade obsidian-tc to version 1.3.1 or later immediately. If multi-vault access is required, ensure tokens include a vault claim matching their intended vault. Avoid running multiple vaults per process as a temporary workaround.

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