CVE-2026-1181: Altium 365 Over-Permissive CORS Configuration Allows Credentialed Cross-Origin Workspace Access

Severity: critical (CVSS 9.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-19 · updated 2026-06-17
Weakness: CWE-284

Description

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.

Affected products

Altium 365: all versions

References

https://www.altium.com/platform/security-compliance/security-advisories

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