CVE-2022-50905: e107 CMS Cross-Site Scripting Vulnerability

CVE-2022-50905 Overview

e107 CMS version 3.2.1 contains multiple cross-site scripting (XSS) vulnerabilities that affect both authenticated users and administrators. The first vulnerability is a reflected XSS that occurs in the news comment functionality when authenticated users interact with the comment form. An attacker can inject malicious JavaScript code through the URL parameter that gets executed when users click outside the comment field after typing content. The second vulnerability involves an upload restriction bypass for authenticated administrators, allowing them to upload SVG files containing malicious code through the media manager's remote URL upload feature, resulting in stored XSS when the uploaded SVG files are accessed.

Critical Impact

Attackers can execute arbitrary JavaScript in users' browsers through reflected XSS in comment forms and stored XSS via malicious SVG file uploads, potentially leading to session hijacking, credential theft, and unauthorized actions on behalf of victims.

Affected Products

• e107 CMS version 3.2.1
• news.php component (comment functionality)
• image.php component (media manager)

Discovery Timeline

• 2026-01-13 - CVE CVE-2022-50905 published to NVD
• 2026-01-13 - Last updated in NVD database

Technical Details for CVE-2022-50905

Vulnerability Analysis

This vulnerability consists of two distinct XSS attack vectors within e107 CMS. The reflected XSS vulnerability in the news comment functionality exploits improper input sanitization of URL parameters. When an authenticated user interacts with the comment form and then clicks outside the input field, malicious JavaScript embedded in the URL is executed within the context of the user's session. This attack requires user interaction but can be delivered through social engineering tactics.

The stored XSS vulnerability takes advantage of insufficient file upload validation in the media manager. Authenticated administrators can upload SVG files via the remote URL upload feature without proper content sanitization. Since SVG files can contain embedded JavaScript, any user accessing these uploaded files will execute the malicious code. This creates a persistent attack vector that affects all visitors who view the compromised media content.

Root Cause

The root cause of these vulnerabilities stems from inadequate input validation and output encoding (CWE-79). In the reflected XSS case, the application fails to properly sanitize URL parameters before rendering them in the page context. For the stored XSS vulnerability, the media manager does not adequately validate or sanitize the contents of uploaded SVG files, allowing embedded script elements to persist and execute when the files are served to users.

Attack Vector

The attack leverages the network attack vector requiring user interaction. For the reflected XSS, an attacker crafts a malicious URL containing JavaScript payload and tricks an authenticated user into clicking it. When the victim interacts with the comment form and then clicks outside the input area, the injected script executes. For the stored XSS, an attacker with administrator privileges uploads a malicious SVG file through the remote URL upload feature. The malicious code persists on the server and executes whenever users access the uploaded file.

The reflected XSS attack flow involves URL parameter injection in the news comment functionality. When a user visits a crafted malicious URL and interacts with the comment form, the JavaScript payload embedded in the URL parameter is reflected back and executed in the browser context. The stored XSS attack flow involves uploading an SVG file containing malicious JavaScript through the media manager's remote upload functionality. Once uploaded, the file is served to any user who accesses it, triggering script execution. For detailed exploitation techniques, refer to the Exploit-DB #50910 entry.

Detection Methods for CVE-2022-50905

Indicators of Compromise

• Unusual URL parameters in news.php requests containing encoded JavaScript or HTML tags
• SVG files uploaded to the media manager containing <script> tags or event handlers
• Web server logs showing requests to news.php with suspicious query string patterns
• Unexpected SVG files in the e107 media directories that contain embedded JavaScript

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block XSS patterns in URL parameters
• Monitor HTTP request logs for encoded script tags (%3Cscript%3E) in query strings targeting news.php
• Implement file integrity monitoring on the e107 media upload directories
• Scan uploaded SVG files for embedded JavaScript using automated content inspection tools

Monitoring Recommendations

• Enable detailed access logging for the e107 application and review logs for suspicious URL patterns
• Set up alerts for administrator file uploads containing SVG format files
• Monitor browser security reports (CSP violations) if Content Security Policy is implemented
• Conduct periodic security scans of the media directory for files containing script elements

How to Mitigate CVE-2022-50905

Immediate Actions Required

• Restrict access to the e107 CMS administrative interface to trusted IP addresses only
• Disable or restrict SVG file uploads through the media manager until patches are applied
• Implement Content Security Policy (CSP) headers to mitigate the impact of XSS attacks
• Review and sanitize existing uploaded SVG files in the media directory

Patch Information

Check the e107 Official Website and e107 Download Page for updated versions that address these vulnerabilities. Review the VulnCheck Advisory on eCMS XSS for additional security guidance. Upgrade to the latest version of e107 CMS as patches become available.

Workarounds

• Implement server-side input validation to sanitize all URL parameters before processing
• Configure the web server to add Content-Disposition: attachment headers for SVG files to prevent inline rendering
• Block SVG file uploads entirely through the media manager configuration
• Deploy a WAF with XSS protection rules in front of the e107 application

# Apache configuration to prevent inline SVG execution
# Add to .htaccess or Apache configuration for e107 media directory

<FilesMatch "\.svg$">
    Header set Content-Disposition "attachment"
    Header set X-Content-Type-Options "nosniff"
    Header set Content-Security-Policy "script-src 'none'"
</FilesMatch>