CVE-2026-42151 — Prometheus Azure AD remote write OAuth client secret exposed via config API

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
prometheus / prometheus	affected < 3.5.3; affected >= 3.6.0, < 3.11.3

CWE

CWE-200, CWE-312

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Prometheus, an open-source monitoring system. The `client_secret` field within the Azure Active Directory (AD) remote write OAuth configuration was incorrectly handled as a plain string instead of a secure Secret type. This misconfiguration allowed any user or process with access to the `/-/config` HTTP API endpoint to view the Azure OAuth client secret in plaintext. This vulnerability leads to information disclosure, potentially compromising the security of integrated Azure AD services.