9.0
CRITICAL CVSS 3.1
CVE-2026-1009
Stored Cross-Site Scripting in Altium Forum Leading to Cross-Customer Data Exposure
Description

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.

INFO

Published Date :

Jan. 15, 2026, 11:15 p.m.

Last Modified :

Jan. 15, 2026, 11:15 p.m.

Remotely Exploit :

Yes !

Source :

4760f414-e1ae-4ff1-bdad-c7a9c3538b79
Affected Products

The following products are affected by CVE-2026-1009 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL 4760f414-e1ae-4ff1-bdad-c7a9c3538b79
Solution
Sanitize all server-side input for forum post content to prevent XSS attacks.
  • Implement robust server-side input sanitization for all user-generated content.
  • Validate and encode user input before rendering it in HTML.
  • Update forum software to the latest secure version.
  • Educate users about safe content submission practices.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-1009.

URL Resource
https://www.altium.com/platform/security-compliance/security-advisories
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-1009 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-1009 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-1009 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-1009 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 4760f414-e1ae-4ff1-bdad-c7a9c3538b79

    Jan. 15, 2026

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
    Added CWE CWE-79
    Added CWE CWE-284
    Added Reference https://www.altium.com/platform/security-compliance/security-advisories
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 9
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact