CVE-2025-66563
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-04

Last updated on: 2025-12-17

Assigner: GitHub, Inc.

Description
Monkeytype is a minimalistic and customizable typing test. In 25.49.0 and earlier, there is improper handling of user input which allows an attacker to execute malicious javascript on anyone viewing a malicious quote submission. quote.text and quote.source are user input, and they're inserted straight into the DOM. If they contain HTML tags, they will be rendered (after some escaping using quotes and textarea tags).
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Meta Information
Published
2025-12-04
Last Modified
2025-12-17
Generated
2026-06-16
AI Q&A
2025-12-05
EPSS Evaluated
2026-06-15
NVD
CVE-2025-66563
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
monkeytype monkeytype to 25.49.0 (exc)
monkeytype monkeytype 25.49.0
Helpful Resources
Exploitability
CWE
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KEV
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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.
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Executive Summary

This vulnerability in Monkeytype (version 25.49.0 and earlier) involves improper handling of user input in quote submissions. Specifically, the fields quote.text and quote.source are user-controlled and are inserted directly into the DOM without proper sanitization. Although some escaping is done using quotes and textarea tags, HTML tags within these inputs can still be rendered, allowing an attacker to execute malicious JavaScript on anyone viewing a malicious quote submission.

Impact Analysis

This vulnerability can lead to cross-site scripting (XSS) attacks, where an attacker can execute malicious JavaScript code in the context of users viewing the affected page. This can result in theft of user data, session hijacking, defacement, or other malicious actions performed on behalf of the victim user.

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