CVE-2025-66563: Monkeytype is a minimalistic and customizable typing test

Q: How do I fix CVE-2025-66563?

monkeytype: upgrade to newer than 25.49.0. Exact commands for each OS are on this page.

Q: Is CVE-2025-66563 being exploited?

CVE-2025-66563 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-66563 affect?

CVE-2025-66563 affects monkeytype. Severity is medium (CVSS 6.1). 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

Q: How urgent is CVE-2025-66563?

Priority 30/100. Public exploit reference

Routine

MEDIUM 6.1UPGRADE

CVE-2025-66563 is a medium-severity flaw (CVSS 6.1) affecting monkeytype. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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).

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-79
Published	2025-12-04
Last modified	2026-10-18

Publisher (CNA): GitHub, Inc. · Vendor: monkeytype

Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-04 23:15 UTCPublished CVE record published
2026-10-18 15:10 UTCUpdated Record last modified

monkeytype monkeytype UPGRADE

Affected: <= 25.49.0

Fixed in: newer than 25.49.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy monkeytype || rpm -q monkeytype || monkeytype --version

2. UPGRADE to newer than 25.49.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade monkeytype

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade monkeytype

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-66563?

monkeytype: upgrade to newer than 25.49.0. Exact commands for each OS are on this page.

Is CVE-2025-66563 being exploited?

CVE-2025-66563 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-66563 affect?

CVE-2025-66563 affects monkeytype. Severity is medium (CVSS 6.1). 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

How urgent is CVE-2025-66563?

Priority 30/100. Public exploit reference

Related CVEs

CVE-2025-59838 MEDIUM 5.4 UPGRADE Monkeytype is a minimalistic and customizable typing test
CVE-2024-41127 HIGH 8.3 UPGRADE Monkeytype is a minimalistic and customizable typing test

References

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