### Impact

Gotify exposes an outdated instance of the [Swagger UI](https://swagger.io/tools/swagger-ui/) API documentation frontend at `/docs` which is susceptible to reflected XSS attacks when loading external Swagger config files.

Specifically, the DOMPurify version included with this version of Swagger UI is vulnerable to a [rendering XSS](https://www.vidocsecurity.com/blog/hacking-swagger-ui-from-xss-to-account-takeovers/) incorporating the mutation payload detailed in [CVE-2020-26870](https://research.securitum.com/mutation-xss-via-mathml-mutation-dompurify-2-0-17-bypass/) which was patched in 2021. This is further tracked in the GitHub Advisory Database as GHSA-QRMM-W75W-3WPX.

An attacker can execute arbitrary JavaScript and potentially take over the account of the user that clicked the link. Keep in mind, the Gotify UI won’t natively expose such a malicious link, so an attacker has to get the user to open the malicious link in a context outside of Gotify.

### Patches

The vulnerability has been fixed in version 2.2.3.

### References

https://github.com/gotify/server/pull/541Read More