CVE-2021-29622: Prometheus is an open-source monitoring system and time series database

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MEDIUM 6.5UPGRADE

CVE-2021-29622 is a medium-severity flaw (CVSS 6.5) affecting prometheus. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 U

Why this priority

EPSS top 3%: very likely to be exploited

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	19.6% (top 3%)
CISA exploited list	No
Weakness	CWE-601
Published	2021-05-19
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: prometheus

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-05-19 20:15 UTCPublished CVE record published
2026-06-17 03:48 UTCUpdated Record last modified

prometheus prometheus UPGRADE

Affected: >= 2.23.0 and < 2.26.1 · 2.27.0 · 2.27.0 rc0

Fixed in: 2.26.1

Safe to downgrade to: a release before 2.23.0

1. Check installed version

apt-cache policy prometheus || rpm -q prometheus || prometheus --version

2. UPGRADE to 2.26.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade prometheus

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade prometheus

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.23.0 (Debian / Ubuntu)

apt-cache madison prometheus sudo apt install prometheus=<VERSION_BEFORE_2.23.0> sudo apt-mark hold prometheus

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list prometheus sudo dnf downgrade prometheus-<VERSION_BEFORE_2.23.0> sudo dnf versionlock add prometheus

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Nuclei scan template: Prometheus - Open Redirect

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-29622?

prometheus: upgrade to 2.26.1. Exact commands for each OS are on this page.

Is CVE-2021-29622 being exploited?

CVE-2021-29622 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-29622 affect?

CVE-2021-29622 affects prometheus. Severity is medium (CVSS 6.5). 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

How urgent is CVE-2021-29622?

Priority 47/100. EPSS top 3%: very likely to be exploited

Software pages

Prometheus vulnerabilities

Related CVEs

CVE-2026-42154 HIGH 7.5 UPGRADE Prometheus is an open-source monitoring system and time series database
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CVE-2026-40179 MEDIUM 6.1 UPGRADE Prometheus is an open-source monitoring system and time series database
CVE-2019-3826 MEDIUM 6.1 UPGRADE DOWNGRADE A stored, DOM based, cross-site scripting (XSS) flaw was found in Prometheus before version 2.7.1

References

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