What is the CVSS score of CVE-2025-66458?

CVE-2025-66458 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.0%.

Which versions of Lookyloo are affected by CVE-2025-66458?

Organizations using Lookyloo should be aware of moderate risk from CVE-2025-66458, a cross-site scripting vulnerability rated CVSS 6.1.. A patch is available.

How to fix or mitigate CVE-2025-66458?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Lookyloo CVE-2025-66458

EUVD-2025-200306 MEDIUM

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

2025-12-02 security-advisories@github.com

XSS Lookyloo

6.1

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

6.1 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

EUVD ID Assigned

Mar 15, 2026 - 14:04 euvd

EUVD-2025-200306

Analysis Generated

Mar 15, 2026 - 14:04 vuln.today

Patch released

Mar 15, 2026 - 14:04 nvd

Patch available

CVE Published

Dec 02, 2025 - 19:15 nvd

MEDIUM 6.1

DescriptionGitHub Advisory

Lookyloo is a web interface that allows users to capture a website page and then display a tree of domains that call each other. Prior to 1.35.3, there are multiple XSS due to unsafe use of f-strings in Markup. The issue requires a malicious 3rd party server responding with a JSON document containing JS code in a script element. This vulnerability is fixed in 1.35.3.

Analysis

Technical ContextAI

Cross-site scripting (XSS) allows injection of client-side scripts into web pages viewed by other users due to insufficient output encoding.

RemediationAI

A vendor patch is available — apply it immediately. Encode all user-supplied output contextually (HTML, JS, URL). Implement Content Security Policy (CSP) headers. Use HTTPOnly and Secure cookie flags.