CVE-2026-42151

CVE-2026-42151 is a high-severity vulnerability in Prometheus with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Description

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 any user or process with access to that endpoint. This issue has been patched in versions 3.5.3 and 3.11.3.

Frequently asked questions

What is CVE-2026-42151?
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 any user or process with access to that endpoint. This issue has been patched in versions 3.5.3 and 3.11.3.
How severe is CVE-2026-42151?
CVE-2026-42151 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-42151 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-42151?
CVE-2026-42151 affects Prometheus. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-42151?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-42151 have an EU (EUVD) identifier?
Yes. CVE-2026-42151 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27089.
When was CVE-2026-42151 published?
CVE-2026-42151 was published on 2026-05-04 and last updated on 2026-07-02.

References

Affected products (1)

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