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Improper Access ControlWeakness · CWE-284

CVE-2026-1181

CRITICAL · 9.0 CVSS v3.1 Published 2026-01-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Altium 365 workspace endpoints had an overly permissive CORS policy allowing credentialed cross-origin requests from Altium-controlled subdomains including forum.live.altium.com. This enabled malicious JavaScript from those origins to access authenticated workspace APIs in the context of a logged-in user, enabling unauthorized data access, administrative actions, and bypass of IP allowlisting including in GovCloud environments.

MitigationRestrict CORS policy to explicitly whitelist only trusted origins rather than allowing all Altium subdomains, and review all external applications hosted on subdomains for vulnerabilities that could be chained with this misconfiguration.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Inspect CORS headers on Altium 365 workspace endpoints
    Send an HTTP request to your Altium 365 workspace URL (such as https://365.altium.com or your organization's custom domain) with an Origin header set to a non-Altium domain (for example, https://example.com). Examine the response headers for Access-Control-Allow-Origin.
    Affected if The Access-Control-Allow-Origin header returns a wildcard (*), the requesting origin itself, or any Altium-controlled subdomain such as forum.live.altium.com, combined with Access-Control-Allow-Credentials set to true.
  2. Verify credentialed requests from Altium subdomains
    Send a cross-origin request from a browser or curl with an Origin header set to https://forum.live.altium.com (or other Altium-controlled subdomains) and with credentials (cookies) included. Check if the response includes Access-Control-Allow-Origin matching that subdomain and Access-Control-Allow-Credentials set to true.
    Affected if The API responds with the Altium subdomain origin allowed and credentials permitted, enabling JavaScript on that subdomain to make authenticated requests on behalf of users.
  3. Check for multiple allowed Altium subdomains
    Test multiple Altium-related subdomains (such as forum.live.altium.com, support.live.altium.com, or any *.altium.com origin) as the Origin header. Determine if all are permitted through CORS in combination with credentials.
    Affected if Any Altium-controlled subdomain is permitted alongside credentials, creating a vector where compromise of that subdomain enables workspace API access.
  4. Examine GovCloud-specific endpoint behavior
    If using Altium 365 GovCloud, test API endpoints from a cross-origin request with an Altium subdomain origin. Verify if the IP allowlist can be bypassed through CORS-enabled requests from those origins.
    Affected if Cross-origin requests from Altium subdomains successfully bypass IP allowlist restrictions on GovCloud endpoints.

Your environment is affected if Altium 365 workspace endpoints return an Altium-controlled subdomain (such as forum.live.altium.com) or a wildcard in the Access-Control-Allow-Origin header while also allowing credentials, enabling cross-origin scripts to access authenticated API data.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict CORS policy to explicitly whitelist only trusted origins rather than allowing all Altium subdomains, and review all external applications hosted on subdomains for vulnerabilities that could be chained with this misconfiguration.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-1181 in production — separate from our analysis above.

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