CVE-2025-27380: Altium Enterprise Server XSS Vulnerability

CVE-2025-27380 Overview

CVE-2025-27380 is an HTML injection vulnerability affecting the Project Release functionality in Altium Enterprise Server (AES) version 7.0.3. This Cross-Site Scripting (XSS) flaw allows authenticated attackers to execute arbitrary JavaScript code in victims' browsers by injecting crafted HTML content into the application.

Critical Impact

Authenticated attackers can leverage this HTML injection vulnerability to execute malicious JavaScript in other users' browser sessions, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of legitimate users.

Affected Products

• Altium Enterprise Server (AES) 7.0.3 on all platforms
• Project Release component within Altium Enterprise Server
• All operating systems running the affected AES version

Discovery Timeline

• 2026-01-22 - CVE CVE-2025-27380 published to NVD
• 2026-01-22 - Last updated in NVD database

Technical Details for CVE-2025-27380

Vulnerability Analysis

This vulnerability is classified under CWE-79 (Improper Neutralization of Input During Web Page Generation), commonly known as Cross-Site Scripting (XSS). The flaw exists within the Project Release functionality of Altium Enterprise Server, where user-supplied HTML content is not properly sanitized before being rendered in the browser.

When an authenticated user submits crafted HTML content through the Project Release feature, the application fails to adequately encode or filter potentially dangerous elements. This allows the injected content to be executed as active code when viewed by other users, breaking the boundary between data and executable code in the web application context.

The attack requires authentication, meaning an attacker must first have valid credentials to the Altium Enterprise Server. However, once authenticated, the attacker can inject malicious payloads that execute in the context of other users' sessions, including potentially those with higher privileges.

Root Cause

The root cause of CVE-2025-27380 is improper input validation and output encoding in the Project Release component. The application fails to sanitize HTML input before storing it and does not properly encode the content when rendering it back to users. This allows HTML and JavaScript code to be interpreted and executed by the victim's browser rather than being treated as plain text data.

Attack Vector

The attack is conducted over the network and requires the attacker to have low-privilege authenticated access to the Altium Enterprise Server. The exploitation flow involves:

1. The attacker authenticates to the Altium Enterprise Server with valid credentials
2. The attacker navigates to the Project Release functionality
3. Crafted HTML content containing malicious JavaScript is submitted through vulnerable input fields
4. When another user (the victim) views the affected Project Release content, the malicious script executes in their browser session
5. The script runs with the privileges of the victim's session, enabling theft of session tokens, CSRF attacks, or other malicious actions

The vulnerability requires user interaction, as a victim must view the page containing the injected content for the attack to succeed. The scope is changed, meaning the vulnerability can affect resources beyond the vulnerable component's security scope.

Detection Methods for CVE-2025-27380

Indicators of Compromise

• Unusual HTML or JavaScript content appearing in Project Release entries
• Unexpected <script>, <iframe>, or event handler attributes in stored data
• User reports of unexpected browser behavior when viewing Project Release content
• Authentication tokens or session data being sent to external domains

Detection Strategies

• Monitor web application logs for suspicious HTML tags or JavaScript patterns in POST requests to Project Release endpoints
• Implement Web Application Firewall (WAF) rules to detect common XSS payloads in request bodies
• Review stored Project Release data for potentially malicious HTML content
• Deploy Content Security Policy (CSP) headers to detect and block inline script execution

Monitoring Recommendations

• Enable detailed logging for all user interactions with the Project Release functionality
• Configure alerts for requests containing common XSS vectors such as <script>, javascript:, or event handlers like onerror, onload
• Monitor outbound network connections from client browsers for potential data exfiltration
• Implement User Behavior Analytics (UBA) to detect anomalous content submissions

How to Mitigate CVE-2025-27380

Immediate Actions Required

• Review Altium's security advisories for available patches or updated versions
• Restrict access to the Project Release functionality to trusted users only
• Implement Web Application Firewall rules to filter potentially malicious HTML input
• Enable Content Security Policy (CSP) headers to mitigate the impact of successful XSS attacks

Patch Information

Altium has published security information regarding this vulnerability. Administrators should consult the Altium Security Advisory page for the latest patch information and remediation guidance. Apply any available security updates to Altium Enterprise Server as soon as possible after testing in a non-production environment.

Workarounds

• Implement strict input validation on the server side to reject HTML content in Project Release fields
• Deploy Content Security Policy headers with script-src 'self' to prevent inline script execution
• Consider using a reverse proxy or WAF to sanitize potentially malicious content before it reaches the application
• Limit user permissions to reduce the attack surface by restricting who can create or modify Project Release entries

# Example Content Security Policy header configuration for Apache
# Add to httpd.conf or .htaccess
Header set Content-Security-Policy "default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'; img-src 'self' data:; frame-ancestors 'self';"