Cross site scripting Vulnerability in backstage Software Catalog
Date: 2023-02
Affected: npm/@backstage/plugin-catalog-backend, npm/@backstage/catalog-model, npm/@backstage/core-components
Attack vector: xss
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2023-25571
CWE: CWE-79
CVSS: 6.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N)

### Impact This vulnerability allows a malicious actor with access to add or modify content in an instance of the Backstage software catalog to inject script URLs in the entities stored in the catalog. If users of the catalog then click on said URLs, that can lead to an XSS attack. ### Patches This vulnerability has been patched in both the frontend and backend implementations. The default `Link` component from `@backstage/core-components` will now reject `javascript:` URLs, and there is a global override of `window.open` to do the same. In addition the catalog model as well as the catalog backend now has additional validation built in that prevents `javascript:` URLs in known annotations. ### Workarounds The general practice of limiting access to modifying catalog content and requiring code reviews greatly helps mitigate this vulnerability. ### For more information If you have any questions or comments about this advisory: * Open an issue in the [Backstage repository](https://github.com/backstage/backstage) * Visit our chat, linked to in the [Backstage README](https://github.com/backstage/backstage)


Mitigations:

Architectural layers (MAESTRO):