How severe is CVE-2025-66563?

CVE-2025-66563 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-66563 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66563?

CVE-2025-66563 affects Monkeytype. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66563?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66563 have an EU (EUVD) identifier?

Yes. CVE-2025-66563 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201320.

When was CVE-2025-66563 published?

CVE-2025-66563 was published on 2025-12-04 and last updated on 2026-06-17.

CVE-2025-66563

CVE-2025-66563 is a medium-severity vulnerability in Monkeytype with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 7.1
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201320
Weakness: CWE-79
Affected product: Monkeytype
Published: 2025-12-04
Last modified: 2026-06-17

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).

Frequently asked questions

What is CVE-2025-66563?: 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).
How severe is CVE-2025-66563?: CVE-2025-66563 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-66563 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66563?: CVE-2025-66563 affects Monkeytype. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66563?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66563 have an EU (EUVD) identifier?: Yes. CVE-2025-66563 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201320.
When was CVE-2025-66563 published?: CVE-2025-66563 was published on 2025-12-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:monkeytype:monkeytype:*:*:*:*:*:*:*:*

More vulnerabilities in Monkeytype

CVE-2024-41127 — High (CVSS 8.3): Monkeytype is a minimalistic and customizable typing test. Monkeytype is vulnerable to Poisoned Pipeline Execution…
CVE-2025-59838 — Medium (CVSS 5.4): Monkeytype is a minimalistic and customizable typing test. In versions 25.36.0 and prior, improper handling of user…

All CVEs affecting Monkeytype →

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

CVE-2025-49410 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC…
CVE-2024-47875 — Critical (CVSS 10.0): DOMPurify is a DOM-only, super-fast, uber-tolerant XSS sanitizer for HTML, MathML and SVG. DOMpurify was vulnerable to…
CVE-2024-6886 — Critical (CVSS 10.0): Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Gitea…
CVE-2023-45144 — Critical (CVSS 10.0): com.xwiki.identity-oauth:identity-oauth-ui is a package to aid in building identity and service providers based on…
CVE-2023-45138 — Critical (CVSS 10.0): Change Request is an pplication allowing users to request changes on a wiki without publishing the changes directly.…
CVE-2022-4361 — Critical (CVSS 10.0): Keycloak, an open-source identity and access management solution, has a cross-site scripting (XSS) vulnerability in the…

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →