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Prometheus Azure AD remote write OAuth client secret exposed via config API

High severity GitHub Reviewed Published Apr 27, 2026 in prometheus/prometheus • Updated May 5, 2026

Package

gomod github.com/prometheus/prometheus (Go)

Affected versions

>= 0.45.2, < 0.311.3

Patched versions

0.311.3

Description

Impact

Users who use Azure AD remote write with OAuth authentication are impacted.

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.

Patches

The problem has been patched by changing ClientSecret in OAuthConfig to Secret. Users should upgrade to 3.11.3 or 3.5.3 LTS.

Workarounds

Users who can not upgrade can switch to Managed Identity or Workload Identity authentication for Azure AD remote write, which do not involve a client secret.

References

@roidelapluie roidelapluie published to prometheus/prometheus Apr 27, 2026
Published by the National Vulnerability Database May 4, 2026
Published to the GitHub Advisory Database May 5, 2026
Reviewed May 5, 2026
Last updated May 5, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(1st percentile)

Weaknesses

Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Learn more on MITRE.

Cleartext Storage of Sensitive Information

The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere. Learn more on MITRE.

CVE ID

CVE-2026-42151

GHSA ID

GHSA-wg65-39gg-5wfj

Source code

Credits

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