CVE-2025-66563: Monkeytype

Medium severity, CVSS 6.1. EPSS: 0.2% chance of exploitation in the next 30 days.

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).

Affected products

• Monkeytype Monkeytype: up to and including 25.49.0

Published 2025-12-04. Last modified 2026-06-17.