CVE-2026-1009: XSS in Altium Live Forum
Platform
other
Component
altium-live-forum
Fixed in
1.2.3
A stored cross-site scripting (XSS) vulnerability has been identified in Altium Live Forum versions 0 through 1.2.2. This flaw arises from insufficient server-side input sanitization of forum post content. Successful exploitation allows an attacker to inject and execute arbitrary JavaScript code within forum posts, potentially compromising user sessions and sensitive data. The vulnerability is resolved in version 1.2.3.
Impact and Attack Scenarios
The impact of this XSS vulnerability is significant. An authenticated attacker can inject malicious JavaScript into forum posts, which are then stored and executed when other users view the affected post. This allows the attacker’s payload to execute in the context of the victim’s authenticated Altium 365 session. This can lead to unauthorized access to workspace data, including sensitive design files and workspace settings. The attacker could potentially steal credentials, modify designs, or perform other malicious actions within the compromised workspace. The requirement for user interaction to view the malicious post slightly mitigates the risk, but widespread forum usage increases the potential for exploitation.
Exploitation Context
CVE-2026-1009 was publicly disclosed on 2026-01-15. No public proof-of-concept (POC) code has been released at the time of writing, but the vulnerability's nature and CRITICAL CVSS score suggest a high likelihood of exploitation. It is not currently listed on the CISA KEV catalog. The requirement for user interaction to trigger the vulnerability may limit its immediate exploitability, but the potential impact warrants careful attention.
Threat Intelligence
Exploit Status
EPSS
0.01% (3% percentile)
CISA SSVC
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- Privileges Required
- Low — any valid user account is sufficient. Basic authenticated access required.
- User Interaction
- Required — victim must take an action: open a file, click a link, or visit a crafted page.
- Scope
- Changed — successful attack can pivot beyond the vulnerable component to other systems or the host OS.
- Confidentiality
- High — complete confidentiality loss. Attacker can read all data: credentials, keys, personal data.
- Integrity
- High — attacker can write, modify, or delete any data: databases, config files, or code.
- Availability
- High — complete crash or resource exhaustion. Full denial of service.
Affected Software
Weakness Classification (CWE)
Timeline
- Reserved
- Published
- Modified
- EPSS updated
Mitigation and Workarounds
The primary mitigation for CVE-2026-1009 is to upgrade Altium Live Forum to version 1.2.3 or later, which includes the necessary input sanitization fixes. If upgrading immediately is not feasible, consider temporarily restricting user permissions within the forum to limit the potential impact of successful exploitation. Monitor forum activity for suspicious posts or unusual user behavior. While a direct WAF rule is difficult to implement without specific payload signatures, general XSS filtering rules can provide a baseline level of protection. After upgrading, confirm the vulnerability is resolved by attempting to inject a simple JavaScript payload into a forum post and verifying that it is not executed.
How to fix
Update Altium Live to a version later than 1.2.2. This will fix the stored XSS vulnerability in the forum. See the Altium security advisory for more details.
CVE Security Newsletter
Vulnerability analysis and critical alerts directly to your inbox.
Frequently asked questions
What is CVE-2026-1009 — XSS in Altium Live Forum?
CVE-2026-1009 is a CRITICAL stored cross-site scripting (XSS) vulnerability in Altium Live Forum versions 0 through 1.2.2, allowing attackers to inject malicious JavaScript into forum posts.
Am I affected by CVE-2026-1009 in Altium Live Forum?
If you are using Altium Live Forum versions 0–1.2.2, you are potentially affected by this vulnerability. Upgrade to version 1.2.3 or later to mitigate the risk.
How do I fix CVE-2026-1009 in Altium Live Forum?
The recommended fix is to upgrade Altium Live Forum to version 1.2.3 or later. Consider temporary restrictions on user permissions if immediate upgrade is not possible.
Is CVE-2026-1009 being actively exploited?
While no public exploits are currently known, the CRITICAL severity and public disclosure suggest a high likelihood of exploitation. Monitor your forum closely.
Where can I find the official Altium advisory for CVE-2026-1009?
Please refer to the official Altium security advisory for detailed information and updates regarding CVE-2026-1009: [https://www.altium.com/security/advisories/altium-live-forum-xss-vulnerability](https://www.altium.com/security/advisories/altium-live-forum-xss-vulnerability)
Is your project affected?
Upload your dependency file and we'll tell you instantly if this and other CVEs hit you.