Improper Input Handling in Monkeytype Typing Test Application
CVE-2025-66563

7.1HIGH

Key Information:

Vendor

Monkeytypegame

Status
Monkeytype
Vendor
CVE Published:
4 December 2025

What is CVE-2025-66563?

The Monkeytype Typing Test application experiences vulnerabilities due to inadequate handling of user input in versions 25.49.0 and earlier. Attackers can exploit this weakness by submitting malicious quotes containing HTML tags. When these quotes are displayed, the application inserts them directly into the DOM without sufficient validation, leading to potential execution of harmful JavaScript on user sessions. This issue emphasizes the importance of rigorous input sanitation to prevent cross-site scripting (XSS) attacks.

Affected Version(s)

monkeytype <= 25.49.0

References

https://github.com/monkeytypegame/monkeytype/security/adv...
x_refsource_CONFIRM
https://github.com/monkeytypegame/monkeytype/commit/d6d06...
x_refsource_MISC

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
High
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.