CVE-2026-1009 CRITICAL

CVE-2026-1009: Stored Cross-Site Scripting in Altium Live Forum Leading to Cross-Customer Data Exposure

Vendor Altium
Product Altium Live
Weakness CWE-79 · XSS
Published January 15, 2026
Last update January 20, 2026

CVSS base score

9.0/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

A stored cross-site scripting (XSS) vulnerability exists in the Altium Forum due to missing server-side input sanitization in forum post content. An authenticated attacker can inject arbitrary JavaScript into forum posts, which is stored and executed when other users view the affected post. Successful exploitation allows the attacker’s payload to execute in the context of the victim’s authenticated Altium 365 session, enabling unauthorized access to workspace data, including design files and workspace settings. Exploitation requires user interaction to view a malicious forum post.

Key dates

02Disclosure timeline

January 15, 2026 CVE published
January 20, 2026 Record updated