# CVE-2026-90882: Open VSX CORS misconfiguration with credential reflection

Source: https://junglewise.ai/threats/cve-2026-90882-the-open-vsx-org-deployment-returned-access-control-allow-origin  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-22. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-90882 · Severity: info · Published 2026-09-22

Open VSX, an extension marketplace for VS Code, was configured to reflect arbitrary website origins in its CORS headers while allowing credentialed requests. This allowed attackers to create a malicious webpage that steals sensitive user data like login tokens and extension information from logged-in users, or create new API tokens with permission to publish and delete extensions.

Technologies: [Eclipse Foundation Open VSX](https://junglewise.ai/threats/technologies/open-vsx). Vendors: [Eclipse Foundation](https://junglewise.ai/threats/vendors/eclipse-foundation).

## Quick answers

**Is CVE-2026-90882 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-90882 being exploited in the wild.

**How severe is CVE-2026-90882?** Informational severity, published 22 September 2026.

**Which products and versions are affected?** Eclipse Foundation Open VSX affected from 2026-04-29 to 2026-09-07.

**Is there a fix for CVE-2026-90882?** 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-2026-90882 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-90882?** Check whether you run Eclipse Foundation Open VSX 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

The open-vsx.org CDN/edge layer incorrectly reflected the requesting origin in Access-Control-Allow-Origin headers together with Access-Control-Allow-Credentials: true on authenticated /user/* endpoints, violating CORS same-origin policy. An attacker could craft a malicious webpage to make credentialed cross-origin requests to user profile endpoints (/user, /user/tokens, /user/namespaces), read CSRF tokens from /user/csrf, and chain these to create new personal access tokens via /user/token/create with publish and delete permissions. The vulnerability existed in the CDN/edge configuration rather than the Open VSX application itself, which correctly configured a single exact origin.

## Affected products

- Eclipse Foundation Open VSX affected from 2026-04-29 to 2026-09-07

## Timeline

- 2026-09-22: disclosed: Vulnerability published

## References

- [https://gitlab.eclipse.org/security/cve-assignment/-/work_items/289](https://gitlab.eclipse.org/security/cve-assignment/-/work_items/289)

## Related threats

- [Eclipse Open VSX stored XSS in unpkg endpoint](https://junglewise.ai/threats/cve-2026-13323-eclipse-open-vsx-stored-xss-in-unpkg-endpoint)
- [Eclipse Open VSX stored XSS in extension icons](https://junglewise.ai/threats/cve-2026-4983-eclipse-open-vsx-stored-xss-in-extension-icons)