Eclipse Foundation · Eclipse Theia · CVE-2026-60009
**Name of the Vulnerable Software and Affected Versions**
Eclipse Theia versions prior to 1.73.2
**Description**
The `@theia/filesystem` backend binds the 'POST /file-upload' endpoint in every filesystem-enabled deployment. The handler processes an absolute path provided by an attacker via the multipart `uri` field and executes `fs.move(tmp, target, { overwrite: true })` without authentication or workspace confinement. In browser-based deployments, the connection token is only enforced during WebSocket upgrades, while the HTTP middleware in `@theia/core` fails to reject tokenless HTTP requests. Since `multipart/form-data` is a CORS-safelisted request type, a cross-origin web page can trigger an unauthenticated arbitrary file write to any absolute path accessible to the backend process. This can lead to remote code execution, such as by overwriting the `~/.bashrc` file.
**Recommendations**
Update to a version newer than 1.73.1.