CVE-2025-67823: Mitel MiContact Center XSS Vulnerability

CVE-2025-67823 Overview

A Cross-Site Scripting (XSS) vulnerability exists in the Multimedia Email component of Mitel MiContact Center Business through version 10.2.0.10 and Mitel CX through version 1.1.0.1. The vulnerability stems from insufficient input validation, allowing an unauthenticated attacker to inject and execute arbitrary scripts in the context of a victim's browser or desktop client application. Successful exploitation requires user interaction and that the email channel feature is enabled.

Critical Impact

Unauthenticated attackers can execute arbitrary scripts in victim browsers or desktop client applications, potentially leading to session hijacking, credential theft, or unauthorized actions on behalf of users.

Affected Products

• Mitel MiContact Center Business through 10.2.0.10
• Mitel CX through 1.1.0.1
• Multimedia Email component (when email channel is enabled)

Discovery Timeline

• 2026-01-15 - CVE CVE-2025-67823 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2025-67823

Vulnerability Analysis

This vulnerability is classified as CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting (XSS). The flaw resides in the Multimedia Email component of Mitel's contact center solutions, where user-supplied input within email content is not properly sanitized before being rendered in the victim's browser or desktop client application.

The attack can be initiated remotely over the network without requiring any prior authentication or privileges. However, successful exploitation requires user interaction—specifically, a user must interact with a malicious email processed by the vulnerable Multimedia Email component. The scope of the vulnerability extends beyond the vulnerable component itself, potentially affecting other components within the victim's security context.

Root Cause

The root cause of this vulnerability is insufficient input validation within the Multimedia Email component. When processing email content, the application fails to properly sanitize or encode user-controlled input before rendering it in the client-side interface. This allows attackers to inject malicious scripts that execute when the email content is displayed to users.

Attack Vector

The attack vector is network-based and requires the following conditions:

1. The target organization must have the email channel feature enabled in their Mitel MiContact Center Business or Mitel CX deployment
2. An attacker crafts a malicious email containing XSS payload
3. The email is processed by the Multimedia Email component
4. When a user views or interacts with the malicious email through the application interface, the injected script executes in their browser or desktop client context

The vulnerability allows attackers to execute arbitrary JavaScript in the victim's session, potentially enabling session hijacking, credential harvesting, phishing attacks, or unauthorized actions performed on behalf of the victim.

Detection Methods for CVE-2025-67823

Indicators of Compromise

• Unusual JavaScript execution patterns in contact center application logs
• Email content containing suspicious script tags, event handlers (e.g., onerror, onload), or encoded payloads
• Unexpected outbound network connections from client workstations running the Mitel applications
• User reports of unusual application behavior when viewing emails through the contact center interface

Detection Strategies

• Monitor email content processed by the Multimedia Email component for common XSS patterns including <script> tags, JavaScript event handlers, and encoded payload signatures
• Implement Content Security Policy (CSP) violation logging to detect script injection attempts
• Deploy web application firewall (WAF) rules to identify and block XSS payloads in incoming email traffic
• Review application logs for anomalous client-side behavior or error patterns indicating script execution

Monitoring Recommendations

• Enable verbose logging on the Multimedia Email component to capture email content processing events
• Monitor client-side application logs for JavaScript errors or unexpected script execution
• Track outbound network connections from endpoints running Mitel contact center applications
• Implement SIEM alerts for patterns consistent with XSS exploitation attempts

How to Mitigate CVE-2025-67823

Immediate Actions Required

• Review the official Mitel Security Advisory MISA-2025-0010 for vendor-specific remediation guidance
• Consider temporarily disabling the email channel feature if it is not business-critical until patches can be applied
• Implement network-level controls to filter potentially malicious email content before it reaches the Multimedia Email component
• Educate users to exercise caution when interacting with email content through the contact center application

Patch Information

Organizations should consult the Mitel Security Advisories page and specifically MISA-2025-0010 for official patch availability and upgrade instructions. Ensure all Mitel MiContact Center Business installations are updated beyond version 10.2.0.10 and Mitel CX installations are updated beyond version 1.1.0.1 once patches become available.

Workarounds

• Disable the email channel feature in the Multimedia Email component if not required for business operations
• Implement strict Content Security Policy (CSP) headers to prevent inline script execution where possible
• Deploy a web application firewall (WAF) with XSS filtering rules in front of the affected application
• Restrict network access to the contact center application to trusted internal networks only
• Consider email content sanitization at the mail gateway level before emails reach the Mitel application

# Example: Restrict access to Mitel application at network level
# Add firewall rules to limit access to trusted networks only
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP