Impact

As users can provide a redirect address for the proxy to send the authenticated user to at the end of the authentication flow. This is expected to be the original URL that the user was trying to access.
This redirect URL is checked within the proxy and validated before redirecting the user to prevent malicious actors providing redirects to potentially harmful sites.

Patches

Patch will provided as a PR. We have improved the regex and are now testing hundreds of cases to verify we block the common redirects that could be used to exploit this vulnerability.

Workarounds

N/A

References

We are now using a list from https://github.com/payloadbox/open-redirect-payload-list to verify more cases within our test suite