CVE-2021-29622

Prometheus is an open-source monitoring system and time series database. In
2.23.0, Prometheus changed its default UI to the New ui. To ensure a
seamless transition, the URL’s prefixed by /new redirect to /. Due to a bug
in the code, it is possible for an attacker to craft an URL that can
redirect to any other URL, in the /new endpoint. If a user visits a
prometheus server with a specially crafted address, they can be redirected
to an arbitrary URL. The issue was patched in the 2.26.1 and 2.27.1
releases. In 2.28.0, the /new endpoint will be removed completely. The
workaround is to disable access to /new via a reverse proxy in front of
Prometheus.