CVE-2025-66823
📋 TL;DR
An HTML injection vulnerability in TrueConf Server 5.5.2.10813 allows attackers to inject malicious HTML code into conference descriptions. When victims view the Conference Info page, the injected content executes in their browser context. This affects all TrueConf Server 5.5.2.10813 installations with conference creation/edit functionality enabled.
💻 Affected Systems
- TrueConf Server
📦 What is this software?
Server by Trueconf
⚠️ Risk & Real-World Impact
Worst Case
Attackers could inject malicious scripts that steal session cookies, redirect users to phishing sites, or perform actions on behalf of authenticated users, potentially leading to account compromise or data theft.
Likely Case
Attackers inject phishing content, deface conference pages, or steal session information from users viewing compromised conference info pages.
If Mitigated
With proper input validation and output encoding, injected HTML would be displayed as plain text rather than executed, preventing any malicious impact.
🎯 Exploit Status
Exploitation requires authenticated access to create/edit conferences. HTML injection payloads are simple to craft and execute when victims view conference info pages.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://trueconf.com
Restart Required: No
Instructions:
1. Monitor TrueConf for security updates. 2. Apply patches when available. 3. Verify fix by testing HTML injection in conference description field.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement server-side input validation to strip or encode HTML tags from conference description fields
Implement input sanitization in conference creation/edit API endpoints
Output Encoding
allApply proper HTML encoding when displaying conference descriptions on the info page
Use HTML entity encoding (e.g., < → <, > → >) for all user-supplied content
🧯 If You Can't Patch
- Restrict conference creation/edit permissions to trusted administrators only
- Implement a web application firewall (WAF) with HTML injection protection rules
🔍 How to Verify
Check if Vulnerable:
Create a conference with description containing <script>alert('test')</script> and check if script executes when viewing conference info pageCheck Version:
Check TrueConf Server version in web interface or configuration filesVerify Fix Applied:
Test HTML injection payloads in conference description field and verify they display as plain text rather than executing📡 Detection & Monitoring
Log Indicators:
- Unusual HTML tags or script content in conference description fields
- Multiple conference creation/edit attempts with HTML payloads
Network Indicators:
- HTTP POST requests to conference creation/edit endpoints containing HTML/script tags
SIEM Query:
source="trueconf" AND (description CONTAINS "<script>" OR description CONTAINS "javascript:")