Vulnerability Description
In Open VSX Registry before 1.0.2, the /vscode/unpkg/ endpoint serves user-supplied HTML files with Content-Type: text/html and without a Content-Security-Policy or Content-Disposition: attachment response header. An unauthenticated attacker can register a publisher account, upload a VSIX containing a crafted HTML payload, and induce an authenticated user to visit the resulting URL. The browser renders the file inline in the open-vsx.org origin context, enabling session token exfiltration, persistent Personal Access Token (PAT) generation, and unauthorized publication of malicious extension versions. Because Open VSX extensions are distributed to VS Code, VSCodium, Cursor, Windsurf, and compatible editors, a compromised extension update constitutes a supply chain attack against all downstream users.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Eclipse | Open Vsx | < 1.0.2 |
Related Weaknesses (CWE)
References
- https://github.com/eclipse-openvsx/openvsx/pull/1922Issue TrackingPatch
- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/485ExploitIssue TrackingVendor Advisory
- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/485ExploitIssue TrackingVendor Advisory
FAQ
What is CVE-2026-13323?
CVE-2026-13323 is a vulnerability with a CVSS score of 4.1 (MEDIUM). In Open VSX Registry before 1.0.2, the /vscode/unpkg/ endpoint serves user-supplied HTML files with Content-Type: text/html and without a Content-Security-Policy or Content-Disposition: attachment res...
How severe is CVE-2026-13323?
CVE-2026-13323 has been rated MEDIUM with a CVSS base score of 4.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-13323?
Check the references section above for vendor advisories and patch information. Affected products include: Eclipse Open Vsx.