Comment 3 for bug 1982676

I confirmed it.

Using "success_url" parameter in an URL was introduced in commit a436b12acc85d474f4e71404de771d7143421eed and the corresponding gerrit review is https://review.opendev.org/c/openstack/horizon/+/270461 .
The affected version is horizon 12.0.0 and later (up to the master).

The URL parameter "success_url" is used to control a page shown after succeeding the snapshot update operation, but passing the full URL is not a good way to achieve the goal. Horizon should not depend on an URL passed from users. It should be decided internally.
Perhaps a fix would be to define a subclass of [1] instead of using "success_url" from request.GET.

[1] https://opendev.org/openstack/horizon/src/branch/master/openstack_dashboard/dashboards/project/snapshots/views.py#L83