Prometheus OAuth Client Secret Exposure via /-/config (pre 3.5.3/3.11.3)
CVE-2026-42151 Published on May 4, 2026
Prometheus Azure AD remote write OAuth client secret exposed via config API
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.
Vulnerability Analysis
CVE-2026-42151 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Types
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2026-42151 has been classified to as an Information Disclosure vulnerability or weakness.
Cleartext Storage of Sensitive Information
The application stores sensitive information in cleartext within a resource that might be accessible to another control sphere. Because the information is stored in cleartext, attackers could potentially read it. Even if the information is encoded in a way that is not human-readable, certain techniques could determine which encoding is being used, then decode the information.
Products Associated with CVE-2026-42151
Want to know whenever a new CVE is published for Prometheus? stack.watch will email you.
Affected Versions
prometheus:- Version < 3.5.3 is affected.
- Version >= 3.6.0, < 3.11.3 is affected.