CVE-2026-1011Network attack vector

Stored XSS via unsanitized support comments

Published Jan 15, 2026 · Updated Jan 15, 2026

Stored XSS in Altium 365's Altium Live 1.1.1.39 and earlier allows remote attackers to execute JavaScript in support-case viewers. The AddComment backend accepts arbitrary HTML and JavaScript from modified POST requests, stores it without server-side sanitization, and renders it verbatim in support cases. Successful exploitation requires another user, including potentially elevated support staff, to view the stored comment, and the script runs in that viewer's browser context.

CVSS severity6.1
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Altium 365's Altium Live 1.1.1.39 and earlier allows remote attackers to execute JavaScript in support-case viewers. The AddComment backend accepts arbitrary HTML and JavaScript from modified POST requests, stores it without server-side sanitization, and renders it verbatim in support cases. Successful exploitation requires another user, including potentially elevated support staff, to view the stored comment, and the script runs in that viewer's browser context.

The record

CVE
CVE-2026-1011
Published
Jan 15, 2026
Updated
Jan 15, 2026
Vendor
Altium
Product
Altium 365
Classifications
CWE-79, CWE-116, CAPEC-63, CAPEC-98, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Altium · Altium 365version=unspecified

Published CVSS scores

6.1AltiumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116Improper Encoding or Escaping of Output
CAPEC-63Cross-Site Scripting
CAPEC-98Phishing
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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