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CVE-2026-42151: Prometheus is an open-source monitoring system and time series database

38
Routine
HIGH 7.5REMOTEUPGRADE

CVE-2026-42151 is a high-severity flaw (CVSS 7.5) 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. Prior to versions 3.5.3 and 3.11.3, the client_secret field in the Azure AD remote write OAuth configuration (storage/remote/azuread) was typed as string instead of Secret. Prometheus redacts fields of type Secret when serving the configuration via the /-/config HTTP API endpoint. Because the field was a plain string, the Azure OAuth client secret was exposed in plaintext to

Why this priority

  • High severity
  • Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score7.5 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance0.4% (top 71%)
CISA exploited listNo
WeaknessCWE-200, CWE-312, CWE-256
Published2026-05-04
Last modified2026-09-10
Publisher (CNA): GitHub, Inc. · Vendor: prometheus

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Last updated 2026-09-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

prometheus prometheus UPGRADE
Affected: >= 2.48.0 and < 3.5.3 · >= 3.6.0 and < 3.11.3
Fixed in: 3.5.3, 3.11.3
Safe to downgrade to: a release before 2.48.0
1. Check installed version
apt-cache policy prometheus || rpm -q prometheus || prometheus --version
2. UPGRADE to 3.5.3 (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 2.48.0 (Debian / Ubuntu)
apt-cache madison prometheus sudo apt install prometheus=<VERSION_BEFORE_2.48.0> 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_2.48.0> 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.

Advisories and coverage

Official advisories

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-2026-42151?

prometheus: upgrade to 3.5.3, 3.11.3. Exact commands for each OS are on this page.

Is CVE-2026-42151 being exploited?

CVE-2026-42151 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-2026-42151 affect?

CVE-2026-42151 affects prometheus. Severity is high (CVSS 7.5). Prometheus is an open-source monitoring system and time series database. Prior to versions 3.5.3 and 3.11.3, the client_secret field in the Azure AD remote write OAuth configuration (storage/remote/azuread) was typed as string instead of Se

How urgent is CVE-2026-42151?

Priority 38/100. High severity; Remotely exploitable, no login, no user action

Software pages

Azure vulnerabilities · Prometheus vulnerabilities

Related CVEs

References

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