Altium 365 Over-Permissive CORS Configuration Allows Credentialed Cross-Origin Workspace Access

published 2026-01-19 9mo ago modified 2026-06-17 4mo ago also EUVD-2026-3218

cvss: 9.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 28%
public exploits: 0; none known

Altium 365 workspace endpoints were configured with an overly permissive Cross-Origin Resource Sharing (CORS) policy that allowed credentialed cross-origin requests from other Altium-controlled subdomains, including forum.live.altium.com. As a result, JavaScript executing on those origins could access authenticated workspace APIs in the context of a logged-in user. When chained with vulnerabilities in those external applications, this misconfiguration enables unauthorized access to workspace data, administrative actions, and bypass of IP allowlisting controls, including in GovCloud environments.

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CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 9mo ago (2026-01-20)

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.0	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Affected products

Altium Altium 365

Classification

Weakness

CWE-942 Permissive Cross-domain Security Policy with Untrusted Domains
CWE-284 Improper Access Control

References

altium.com /platform/security-compliance/security-advisories

Sources

CVE List CVE-2026-1181
NVD CVE-2026-1181

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