CVE-2025-62800
BaseFortify
Publication date: 2025-10-28
Last updated on: 2025-11-07
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| jlowin | fastmcp | to 2.13.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a reflected cross-site scripting (XSS) issue in FastMCP versions prior to 2.13.0. It occurs in the OAuth client callback page (oauth_callback.py) where user-controlled values are inserted into the HTML without proper escaping. This allows an attacker to execute arbitrary JavaScript code in the context of the callback server's origin.
How can this vulnerability impact me? :
An attacker exploiting this vulnerability can execute arbitrary JavaScript in the context of the affected server, potentially leading to session hijacking, theft of sensitive information, or performing actions on behalf of the user without their consent.
What immediate steps should I take to mitigate this vulnerability?
Upgrade FastMCP to version 2.13.0 or later, as this version contains the fix for the reflected cross-site scripting vulnerability in the OAuth client callback page.