CVE-2025-55006: Frappe Learning RCE Vulnerability

CVE-2025-55006 Overview

CVE-2025-55006 is a stored cross-site scripting (XSS) vulnerability in Frappe Learning, an open-source learning management system. The flaw exists in the image upload functionality, which fails to sanitize Scalable Vector Graphics (SVG) files before storing them. Authenticated users can upload SVG files containing embedded JavaScript, which then executes in the browsers of other users who view the content. The issue affects versions 2.33.0 and below. A fix is planned for version 2.34.0.

Critical Impact
Authenticated attackers can execute arbitrary JavaScript in victim browsers, enabling session hijacking, account takeover, and unauthorized actions within the Frappe Learning application.

Affected Products

Frappe Learning versions 2.33.0 and below
Component: frappe:learning
CPE: cpe:2.3:a:frappe:learning:*:*:*:*:*:*:*:*

Discovery Timeline

2025-08-09 - CVE-2025-55006 published to NVD
2025-10-06 - Last updated in NVD database

Technical Details for CVE-2025-55006

Vulnerability Analysis

The vulnerability is a stored XSS condition categorized under improper input validation [CWE-20]. Frappe Learning accepts SVG files through its image upload feature without stripping active content. SVG is an XML-based format that natively supports <script> elements and JavaScript event handlers such as onload and onclick. When the application serves these files inline to other users, the browser parses the SVG and executes the embedded scripts in the application's origin context.

Exploitation requires only low-privilege authenticated access. The attack scope extends to any user who later renders the uploaded file, including instructors and administrators. Successful execution runs in the victim's session context, allowing the attacker to steal authentication cookies, perform actions on behalf of the victim, or pivot to administrative functionality.

Root Cause

The upload handler treats SVG files as benign image content. It does not strip <script> tags, JavaScript event handlers, or external entity references before storage. The application also serves the files with a content type that the browser will parse and execute rather than treating them as opaque downloads.

Attack Vector

An authenticated user crafts an SVG file containing a <script> element or an event handler such as onload that calls JavaScript. The attacker uploads the file through the image upload interface, for example as a course thumbnail, profile picture, or lesson asset. When another user requests the resource, the browser renders the SVG inline and executes the embedded payload. The payload runs with the victim's privileges and full access to the application's session cookies and DOM.

For technical details, refer to the GitHub Security Advisory GHSA-mvxw-r9x4-3vrr.

Detection Methods for CVE-2025-55006

Indicators of Compromise

SVG files in the Frappe Learning file storage containing <script> tags, javascript: URIs, or event handler attributes such as onload, onclick, or onerror
Unexpected outbound requests from user browsers to attacker-controlled domains after viewing learning content
Anomalous administrative actions originating from sessions that recently rendered uploaded media

Detection Strategies

Scan the files directory and database File records for uploads with the .svg extension and inspect their contents for executable elements
Review web server access logs for SVG file requests followed by unusual API activity from the same session
Monitor browser Content Security Policy (CSP) violation reports for inline script execution on pages that render user-uploaded media

Monitoring Recommendations

Enable audit logging on the Frappe File doctype to track upload events, including uploader identity and MIME type
Alert on uploads where the file extension is .svg or the MIME type is image/svg+xml
Correlate authentication events and privileged action logs with recent media views to identify session abuse

How to Mitigate CVE-2025-55006

Immediate Actions Required

Upgrade Frappe Learning to version 2.34.0 or later once released by the vendor
Audit existing uploaded SVG files and remove any containing scripts or event handlers
Restrict the upload feature to trusted user roles until the patch is applied

Patch Information

The maintainers have indicated that a fix is planned for version 2.34.0. Until the patched release is available, administrators should apply the workarounds below. Track release status through the Frappe LMS GitHub repository and the official advisory.

Workarounds

Block SVG uploads at the web server or reverse proxy layer by rejecting requests with Content-Type: image/svg+xml or files ending in .svg
Serve all user-uploaded files with Content-Disposition: attachment to prevent inline rendering in the browser
Deploy a strict Content Security Policy that disallows inline scripts on pages rendering user content
Process uploaded SVG files through a sanitizer such as DOMPurify or svg-sanitizer to strip scripts and event handlers before storage

bash

# Example nginx configuration to block SVG uploads and force attachment download
location /files/ {
    if ($request_filename ~* \.svg$) {
        return 403;
    }
    add_header Content-Disposition "attachment";
    add_header Content-Security-Policy "default-src 'self'; script-src 'self'; object-src 'none'";
}