CVE-2021-29622: Arbitrary redirects under /new endpoint

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 19.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-05-19 · updated 2026-06-17
Weakness: CWE-601

Description

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.

Affected products

prometheus: from 2.23.0 before 2.26.1; 2.27.0, 2.27.0-rc0 — fixed in 2.26.1

How to fix

Upgrade to a fixed version: prometheus 2.26.1. Check the vendor advisory for mitigations.

References

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