CVE-2024-31027: GUnet Open eClass XSS Vulnerability

CVE-2024-31027 Overview

CVE-2024-31027 is a stored cross-site scripting (XSS) vulnerability in the Greek Universities Network (GUnet) Open eClass Platform version 3.15. The flaw resides in the user registration functionality, where the last name, first name, and username parameters accept unsanitized input. A remote attacker can inject arbitrary JavaScript that executes in the browser of any user who views the affected profile data.

Open eClass is a widely deployed e-learning platform used across Greek academic institutions, making stored XSS impactful for administrator and student sessions alike.

Critical Impact
Attackers can persist malicious JavaScript through registration, hijack authenticated sessions, steal credentials, and pivot to administrative accounts within the learning management system.

Affected Products

Greek Universities Network (GUnet) Open eClass Platform v3.15
Deployments exposing the public user registration form
Instances rendering user profile data without contextual output encoding

Discovery Timeline

2026-09-29 - CVE-2024-31027 published to the National Vulnerability Database
2026-09-29 - Last updated in NVD database

Technical Details for CVE-2024-31027

Vulnerability Analysis

The vulnerability is a stored cross-site scripting flaw [CWE-79] in the self-service user registration workflow of Open eClass 3.15. The application persists the first name, last name, and username fields to the database without stripping or encoding HTML control characters. When these values are later rendered in user listings, profile pages, or administrative dashboards, the browser interprets the injected markup as executable script.

Because the payload is stored server-side, exploitation does not require social engineering victims into clicking a crafted link. Any authenticated user or administrator who loads a page displaying the attacker-controlled profile triggers execution automatically.

Refer to the public technical write-up for CVE-2024-31027 for reproduction details.

Root Cause

The root cause is missing input validation combined with absent output encoding on personally identifiable fields. The registration handler treats name and username values as free-form strings and stores raw HTML. The rendering templates then emit these values directly into the HTML body context, allowing <script> tags and event handler attributes to execute.

Attack Vector

An unauthenticated remote attacker submits the public registration form with JavaScript payloads embedded in the firstname, lastname, or username fields. Once an administrator reviews pending registrations or another user browses the attacker's profile, the payload runs in the victim's session context. This enables session cookie theft, forced actions via the eClass administrative API, and defacement of course content.

The vulnerability is described in prose only because no verified exploit code is published in the referenced advisory.

Detection Methods for CVE-2024-31027

Indicators of Compromise

Registration records containing HTML tags, angle brackets, or javascript: URIs in firstname, lastname, or username columns
Outbound requests from user browsers to unfamiliar domains sourced from eClass profile pages
Unexpected session cookie exfiltration events correlated with visits to the user directory
New administrative accounts or privilege changes shortly after suspicious registrations

Detection Strategies

Query the eClass user database for stored values matching regular expressions such as <script, onerror=, or onload= in name fields
Enable Content Security Policy (CSP) reporting to capture inline script violations originating from eClass pages
Review web server access logs for POST requests to /modules/auth/registration.php containing URL-encoded angle brackets

Monitoring Recommendations

Alert on anomalous JavaScript execution and DOM modifications from eClass origins using browser telemetry
Correlate registration events with subsequent administrator page views to detect payload triggering
Monitor for session token reuse from unexpected IP addresses following administrator logins

How to Mitigate CVE-2024-31027

Immediate Actions Required

Audit all existing user records for HTML or script content in name and username fields and sanitize or remove malicious entries
Temporarily disable public self-registration on Open eClass 3.15 instances until a patched build is deployed
Force password resets and revoke active sessions for administrators who accessed the user directory
Deploy a web application firewall rule blocking angle brackets and script keywords in registration parameters

Patch Information

No vendor patch identifier is listed in the referenced advisory. Administrators should track updates from the Greek Universities Network (GUnet) Open eClass project and upgrade beyond version 3.15 as soon as a fixed release is published. Consult the CVE-2024-31027 analysis for current remediation status.

Workarounds

Apply server-side input validation that rejects any registration field containing HTML control characters
Implement contextual output encoding in all templates rendering user profile fields
Enforce a strict Content Security Policy that disallows inline scripts and untrusted script sources
Require administrator approval for new registrations and review submissions in a sandboxed context

bash

# Example nginx rule blocking angle brackets in registration POST bodies
location /modules/auth/registration.php {
    if ($request_method = POST) {
        if ($request_body ~* "(<|%3C).*(script|img|svg|iframe)") {
            return 403;
        }
    }
    proxy_pass http://eclass_backend;
}