CVE-2025-51489
📋 TL;DR
A stored XSS vulnerability in MoonShine versions before 3.12.5 allows attackers to upload malicious SVG files when creating or updating articles. When users open these SVG files, arbitrary JavaScript executes in their browser context. This affects all MoonShine deployments running vulnerable versions.
💻 Affected Systems
- MoonShine
📦 What is this software?
Moonshine by Moonshine
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal session cookies, perform actions as authenticated users, redirect to malicious sites, or compromise user accounts through client-side attacks.
Likely Case
Attackers with article creation/update privileges could embed malicious scripts affecting users who view the SVG files, potentially leading to session hijacking or credential theft.
If Mitigated
With proper input validation and content security policies, the impact is limited to isolated client-side effects without server compromise.
🎯 Exploit Status
Exploitation requires authenticated access with article management privileges. SVG files with embedded JavaScript payloads bypass existing filters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.12.5
Vendor Advisory: https://github.com/moonshine-software/moonshine
Restart Required: No
Instructions:
1. Update MoonShine to version 3.12.5 or later using composer update moonshine/moonshine. 2. Verify the update completed successfully. 3. Clear any cached files or assets.
🔧 Temporary Workarounds
Disable SVG uploads
allTemporarily disable SVG file upload functionality in article creation/update forms
Implement Content Security Policy
allAdd CSP headers to restrict script execution from untrusted sources
🧯 If You Can't Patch
- Restrict article creation/update permissions to trusted users only
- Implement WAF rules to block SVG files with JavaScript content
🔍 How to Verify
Check if Vulnerable:
Check MoonShine version in composer.json or via composer show moonshine/moonshineCheck Version:
composer show moonshine/moonshine | grep versionVerify Fix Applied:
Confirm version is 3.12.5 or higher and test SVG upload with script payloads📡 Detection & Monitoring
Log Indicators:
- Unusual SVG file uploads
- Multiple article updates from single user
- Requests to SVG files with suspicious parameters
Network Indicators:
- SVG files containing script tags or JavaScript code in uploads
- Unusual outbound connections after SVG file access
SIEM Query:
source="moonShine" AND (file_extension="svg" AND (content="<script" OR content="javascript:"))