CVE-2026-42151

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-200 CWE-200

CWE-312 CWE-312

Affected Products

Vendor	Product	Versions
prometheus	prometheus	2.48.0 — 3.5.3
prometheus	prometheus	3.6.0 — 3.11.3

References

Advisories & Patches

https://github.com/prometheus/prometheus/pull/18587 https://github.com/prometheus/prometheus/pull/18590 https://github.com/prometheus/prometheus/security/advisories/GHSA-wg65-39gg-5wfj

Other References

https://github.com/prometheus/prometheus/releases/tag/v3.11.3 https://github.com/prometheus/prometheus/releases/tag/v3.5.3

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-42151? +

CVE-2026-42151 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-42151? +

CVE-2026-42151 affects products from prometheus, specifically: prometheus. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-42151? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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