Open Vsx

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.Show less

Open VSX Registry does not sanitize SVG files uploaded as extension icons prior to storage, and serves them with Content-Type: image/svg+xml without security headers such as Content-Security-Policy or Content-Disposition: attachment. This allows an attacker to publish an extension with a malicious SVG icon and achieve stored cross-site scripting (XSS) when a user navigates directly to the icon URL. On deployments using local storage, script execution occurs within the Open VSX application origin, enabling session hijacking, authentication token theft, and unauthorized extension publishing. On deployments backed by external storage (such as open-vsx.org with an S3-backed CDN), execution is confined to the storage origin, reducing impact but still permitting phishing attacks and credential harvesting through attacker-crafted pages.Show less

A vulnerability in the Eclipse Open VSX Registry’s automated publishing system could have allowed unauthorized uploads of extensions. Specifically, the system’s build scripts were executed without proper isolation, potentially exposing a privileged token. This token enabled the publishing of new extension versions under any namespace, including those not controlled by an attacker. However, it did not permit deletion of existing extensions, overwriting of published versions, or access to administrative features of the registry. The issue was reported on May 4, 2025, fully resolved by June 24, and followed by a comprehensive audit. No evidence of compromise was found, though 81 extensions were proactively deactivated as a precaution. The standard publishing process remained unaffected. Recommendations have been issued to mitigate similar risks in the future.Show less

In OpenVSX version v0.9.0 to v0.20.0, the /user/namespace/{namespace}/details API allows a user to edit all namespace details, even if the user is not a namespace Owner or Contributor. The details include: name, description, website, support link and social media links. The same issues existed in /user/namespace/{namespace}/details/logo and allowed a user to change the logo.Show less