CVE-2024-31026: GUnet Open eClass Platform RCE Vulnerability

CVE-2024-31026 Overview

CVE-2024-31026 affects the Greek Universities Network (GUnet) Open eClass Platform version 3.15. The vulnerability resides in the chat input field within the course module. A remote attacker can inject arbitrary HTML content through this input field, which the application renders without proper sanitization. The public proof of concept demonstrates HTML injection that can be leveraged for phishing, content spoofing, or client-side script execution depending on the browser context. Open eClass is widely deployed across Greek academic institutions for e-learning, making authenticated students and instructors potential targets.

Critical Impact
A remote attacker can inject arbitrary HTML through the course chat input field, enabling content spoofing and potential client-side code execution against other users of the course.

Affected Products

GUnet Open eClass Platform v3.15
Deployments of Open eClass with the course chat module enabled
Any downstream forks that inherit the unsanitized chat input handling

Discovery Timeline

2026-09-29 - CVE-2024-31026 published to NVD
2026-09-29 - Last updated in NVD database

Technical Details for CVE-2024-31026

Vulnerability Analysis

The vulnerability is an HTML injection flaw in the course module chat feature of Open eClass v3.15. User-supplied text sent through the chat input field is stored and later rendered to other participants without adequate output encoding or input sanitization. Because the chat surface is shared among enrolled students and instructors, malicious markup delivered by one participant is rendered in the browsers of every viewer of that course chat.

The public proof of concept documents the injection point and the rendered payload. Depending on the payload, an attacker can insert fake login prompts, misleading course notices, or scripted elements that alter the appearance and behavior of the chat page.

Root Cause

The root cause is missing input validation and output encoding on the chat message field in the course module. The application accepts raw HTML from the client, persists it, and returns it to other clients where the browser parses and renders the injected markup. Standard defenses such as HTML entity encoding, an allowlist-based sanitizer, or a strict Content Security Policy are not applied to this input path.

Attack Vector

An authenticated user with access to a course chat submits a crafted message containing HTML tags or scripted attributes. The server stores the message and delivers it to other course participants. When their browsers render the chat, the injected content executes in the origin of the Open eClass instance. This can be used to phish credentials by overlaying a fake login form, redirect users to attacker-controlled sites, or perform actions on behalf of the victim within the session.

No verified exploit code is included here. Refer to the public write-up and proof of concept for reproduction details.

Detection Methods for CVE-2024-31026

Indicators of Compromise

Chat messages containing HTML tags such as <script>, <iframe>, <img onerror=...>, or <form> inside course chat logs
Unexpected outbound requests from user browsers to unfamiliar domains originating from the Open eClass chat page
Reports from students or instructors of unusual login prompts, popups, or page defacement inside a course chat

Detection Strategies

Query the chat message database table for stored entries containing angle brackets, event handler attributes, or javascript: URIs
Enable web server access logging and search POST requests to chat endpoints for payloads containing encoded HTML tags
Deploy a web application firewall rule that flags chat submissions containing script tags, iframe tags, or on-event attributes

Monitoring Recommendations

Monitor the Open eClass application logs for authenticated sessions that repeatedly submit oversized or markup-heavy chat messages
Alert on Content Security Policy violation reports if CSP is deployed in report-only mode
Track user reports of visual anomalies in course chats through the institutional help desk workflow

How to Mitigate CVE-2024-31026

Immediate Actions Required

Disable the course chat module in the Open eClass administration panel until a patched release is deployed
Review stored chat messages and purge entries containing HTML markup or scripted payloads
Rotate session cookies and require re-authentication for users who may have viewed a poisoned chat

Patch Information

At the time of publication, no vendor advisory or patched release identifier is listed in the NVD entry for CVE-2024-31026. Administrators should track the GUnet Open eClass project release notes and apply the first upstream version that addresses HTML injection in the course chat module.

Workarounds

Restrict access to the chat module to trusted user roles through Open eClass access controls
Deploy a reverse proxy or web application firewall rule that strips or blocks HTML tags in requests to the chat endpoint
Configure a strict Content Security Policy that disallows inline scripts and untrusted script sources for the Open eClass origin

bash

# Example nginx rule to block obvious HTML injection payloads on the chat endpoint
location ~* /modules/chat/ {
    if ($request_body ~* "(<script|<iframe|onerror=|javascript:)") {
        return 403;
    }
    proxy_pass http://openeclass_backend;
}