CVE-2025-11966: vert.x XSS — Exploit & Fix

Description

In Eclipse Vert.x versions [4.0.0, 4.5.21] and [5.0.0, 5.0.4], when "directory listing" is enabled, file and directory names are inserted into generated HTML without proper escaping in the href, title, and link attributes. An attacker who can create or rename files or directories within a served path can craft filenames containing malicious script or HTML content, leading to stored cross-site scripting (XSS) that executes in the context of users viewing the affected directory listing.

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CVSS v3.1 Score

6.4

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

CWE-80 CWE-80

Affected Products

Vendor	Product	Versions
eclipse	vert.x	4.0.0 — 4.5.22
eclipse	vert.x	5.0.0 — 5.0.5

References

Advisories & Patches

https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/303

Exploits

https://gitlab.eclipse.org/security/vulnerability-reports/-/issues/303

Frequently Asked Questions

What is CVE-2025-11966? +

In Eclipse Vert.x versions [4.0.0, 4.5.21] and [5.0.0, 5.0.4], when "directory listing" is enabled, file and directory names are inserted into generated HTML without proper escaping in the href, title, and link attributes. An attacker who can create or rename files or directories within a served path can craft filenames containing malicious script or HTML content, leading to stored cross-site scripting (XSS) that executes in the context of users viewing the affected directory listing. It has a CVSS v3.1 base score of 6.4 (MEDIUM).

How severe is CVE-2025-11966? +

CVE-2025-11966 has a CVSS v3.1 score of 6.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-11966? +

CVE-2025-11966 affects products from eclipse, specifically: vert.x. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-11966? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2025-11966