# CVE-2026-42277: Onyx AI Platform IDOR in chat file download endpoint

Source: https://junglewise.ai/threats/cve-2026-42277-onyx-ai-platform-idor-in-chat-file-download-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-08. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-42277 · Severity: medium · CVSS 6.5 · Published 2026-05-08

Onyx is an open-source AI platform used for managing chat sessions and document uploads. A security flaw allows any logged-in user to download files uploaded by other users, including confidential documents and chat attachments, if they know the file's unique identifier. This could lead to the unauthorized exposure of sensitive corporate data or private conversations.

Vendors: [Onyx](https://junglewise.ai/threats/vendors/onyx).

## Quick answers

**Is CVE-2026-42277 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42277 being exploited in the wild.

**How severe is CVE-2026-42277?** Medium severity, with a CVSS score of 6.5, published 8 May 2026.

**Which products and versions are affected?** Onyx AI Platform < 3.0.9, >= 3.1.0 < 3.1.6, >= 3.2.0 < 3.2.6.

**Is there a fix for CVE-2026-42277?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-42277 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-42277?** Check whether you run Onyx AI Platform at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An Insecure Direct Object Reference (IDOR) vulnerability exists in the GET /chat/file/{file_id} endpoint of the Onyx AI platform. While the endpoint requires authentication, it fails to perform an ownership check to ensure the requesting user is authorized to access the specific file_id provided. An attacker with a valid account can retrieve any file by supplying its UUID, as the backend logic in chat_backend.py discards the user object and fetches the file record solely based on the identifier. This issue affects versions prior to 3.0.9, 3.1.6, and 3.2.6, where patches have been implemented to enforce proper authorization.

## Affected products

- Onyx Onyx AI Platform < 3.0.9, >= 3.1.0 < 3.1.6, >= 3.2.0 < 3.2.6

## Timeline

- 2026-04-29: advisory: GitHub Security Advisory published
- 2026-05-08: disclosed: CVE published to NVD

## References

- [https://github.com/onyx-dot-app/onyx/security/advisories/GHSA-vg3h-35f7-7w6r](https://github.com/onyx-dot-app/onyx/security/advisories/GHSA-vg3h-35f7-7w6r)