Stored XSS via Unescaped Filenames in Vert.x Directory Listing (4.0-5.0)
CVE-2025-11966 Published on October 22, 2025
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.
Vulnerability Analysis
CVE-2025-11966 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2025-11966. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Types
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2025-11966 has been classified to as a XSS vulnerability or weakness.
What is a Basic XSS Vulnerability?
The software receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. This may allow such characters to be treated as control characters, which are executed client-side in the context of the user's session. Although this can be classified as an injection problem, the more pertinent issue is the improper conversion of such special characters to respective context-appropriate entities before displaying them to the user.
CVE-2025-11966 has been classified to as a Basic XSS vulnerability or weakness.
Products Associated with CVE-2025-11966
stack.watch emails you whenever new vulnerabilities are published in Eclipse Vert X or Red Hat Kafka. Just hit a watch button to start following.
Affected Versions
Eclipse Foundation Vert.x:- Version 4.0.0 and below 4.5.22 is affected.
- Version 5.0.0 and below 5.0.5 is affected.
Vulnerable Packages
The following package name and versions may be associated with CVE-2025-11966
| Package Manager | Vulnerable Package | Versions | Fixed In |
|---|---|---|---|
| maven | io.vertx:vertx-web | < 4.5.22 | 4.5.22 |
| maven | io.vertx:vertx-web | >= 5.0.0, <= 5.0.4 | 5.0.5 |
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.