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CVE-2026-54618— Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user

Quick assessment

Affected
jimprosser obsidian-web-mcp
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Obsidian Web MCP 是 Obsidian 知识库（vault）的一个安全远程 MCP 服务器。在 0.2.0 版本之前， 端点会在未执行登录、授权确认或会话检查的情况下直接签发授权码，而 端点又能将该授权码兑换为静态令牌 ，且在此过程中未对客户端进行身份认证。因此，任何能够访问目标隧道部署环境的未认证远程调用者均可调用 接口，并对整个知识库执行 （读取）、 （写入）、 （搜索）、 （列表）、 （移动）和 （删除）等操作。可选的 PKCE 机制无法阻止由攻击者发起的授权流程，而未认证的 端点还会通过返回

CVSS 9.4 · Critical

Affected Version Matrix 1

VendorProduct Version RangeStatus
jimprosser obsidian-web-mcp < 0.2.0 affected
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I. Basic Information for CVE-2026-54618

Vulnerability Information
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Vulnerability Title
Obsidian Web MCP: Unauthenticated vault access: /oauth/authorize auto-approves without authenticating the user
Source: CVE Program / CVE List V5
Vulnerability Description
Obsidian Web MCP is a secure remote MCP server for Obsidian vaults. Prior to 0.2.0, /oauth/authorize issues an authorization code without a login, consent, or session check, and /oauth/token can exchange that code for the static VAULT_MCP_TOKEN without authenticating a client. An unauthenticated remote caller who can reach the intended tunnel deployment can therefore call /mcp and use vault_read, vault_write, vault_search, vault_list, vault_move, and vault_delete against the entire vault. Optional PKCE does not prevent an attacker-initiated flow, and unauthenticated /oauth/register also exposes a client_credentials path by returning the configured VAULT_OAUTH_CLIENT_SECRET. This issue is fixed in version 0.2.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
关键功能的认证机制缺失
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
jimprosser obsidian-web-mcp < 0.2.0 -

II. Public POCs for CVE-2026-54618

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III. Intelligence Information for CVE-2026-54618

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Patches & Fixes for CVE-2026-54618 (3)

Vendor Advisories for CVE-2026-54618 (1)

IV. Related Vulnerabilities

Same weakness: CWE-306

V. Comments for CVE-2026-54618

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