What’s Vulnerable › Vulnerabilities

CVE-2025-66563: Monkeytype vulnerable to stored XSS in approve quotes page

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-12-04 · updated 2026-10-18
• Weakness: CWE-79

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).

Affected products

• monkeytypegame monkeytype: through 25.49.0

References

• https://github.com/monkeytypegame/monkeytype/commit/d6d062a77132ba7d6ba3b482d46ae329d3b8d695
• https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-mfjh-9552-8g27
• https://github.com/monkeytypegame/monkeytype/security/advisories/GHSA-mfjh-9552-8g27

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