This affects the package hello.js before 1.18.6. The code get the param oauth_redirect from url and pass it to location.assign without any check and sanitisation. So we can simply pass some XSS payloads into the url param oauth_redirect, such as javascript:alert(1).

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-7741
• MrSwitch/hello.js@d6f5137
• https://github.com/MrSwitch/hello.js/blob/3b79ec93781b3d7b9c0b56f598e060301d1f3e73/dist/hello.all.js%23L1545
• https://snyk.io/vuln/SNYK-JS-HELLOJS-1014546