CVE-2021-29622: Arbitrary redirects under /new endpoint
Impact
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 (e.g.: http://127.0.0.1:9090/new/new<url>), they can be redirected to an arbitrary URL.
e.g. if a user visits http://127.0.0.1:9090/new/newhttp://www.google.com/, they will be redirected to http://google.com.
Patches
The issue will be patched in 2.26.1 and 2.27.1 releases. In 2.28.0, the /new endpoint will be removed completely.
Workarounds
The workaround is to disable access to /new via a reverse proxy in front of Prometheus.
Note: Users who use a --web.external-url= flag with a path (e.g. --web.external-url=http://example.com/prometheus) are not affected.
For more information
If you have any questions or comments about this advisory, please use our community channels (https://prometheus.io/community). Our security policy is available at https://prometheus.io/docs/operating/security/
Other sources
An open redirect vulnerability was found in Prometheus. By specially crafted URL and a /new endpoint, an attacker can redirect user to any other URL.
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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2021-29622?
The severity of CVE-2021-29622 is classified as medium due to the potential for open redirect attacks.
How do I fix CVE-2021-29622?
To fix CVE-2021-29622, upgrade Prometheus to version 2.27.1 or later.
Which versions of Prometheus are affected by CVE-2021-29622?
Prometheus versions from 2.23.0 to 2.26.1 are affected by CVE-2021-29622.
What is an open redirect vulnerability like CVE-2021-29622?
An open redirect vulnerability allows an attacker to redirect users to malicious URLs when they click on specially crafted links.
Are there any known exploits for CVE-2021-29622?
As of the current information available, there are no specific known exploits actively targeting CVE-2021-29622.