Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2025-69196— FastMCP OAuth Proxy token reuse across MCP servers

Quick assessment

Affected
jlowin fastmcp
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.

FastMCP是Jeremiah Lowin个人开发者的一个MCP服务器构建软件。 FastMCP 2.14.2之前版本存在安全漏洞，该漏洞源于服务器未正确处理客户端在授权和令牌请求中提交的资源参数，可能导致令牌被错误地颁发给初始化时传递给OAuthProxy的base_url。

AI Predicted 7.5 Difficulty: Easy EPSS 0.36% · P29

Possible ATT&CK Techniques 1 AI

T1528 · Steal Application Access Token

Affected Version Matrix 1

VendorProduct Version RangeStatus
jlowin fastmcp < 2.14.2 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2025-69196

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
FastMCP OAuth Proxy token reuse across MCP servers
Source: CVE Program / CVE List V5
Vulnerability Description
FastMCP is the standard framework for building MCP applications. Prior to version 2.14.2, the server does not properly respect the resource parameter submitted by the client in the authorization and token request. Instead of issuing the token explicitly for the MCP server, the token is issued for the base_url passed to the OAuthProxy during initialization. This issue has been patched 2.14.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
授权机制不正确
Source: CVE Program / CVE List V5
Vulnerability Title
FastMCP 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FastMCP是Jeremiah Lowin个人开发者的一个MCP服务器构建软件。 FastMCP 2.14.2之前版本存在安全漏洞，该漏洞源于服务器未正确处理客户端在授权和令牌请求中提交的资源参数，可能导致令牌被错误地颁发给初始化时传递给OAuthProxy的base_url。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
jlowin fastmcp < 2.14.2 -

II. Public POCs for CVE-2025-69196

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2025-69196

请登录查看更多情报信息。

Vendor Advisories for CVE-2025-69196 (1)

IV. Related Vulnerabilities

Same product: fastmcp
Same vendor: jlowin
Same weakness: CWE-863

V. Comments for CVE-2025-69196

No comments yet

Leave a comment