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CVE-2026-42151: 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.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-42151 can expose an Azure OAuth client secret from affected Prometheus servers through the configuration API. This is a confidentiality issue: anyone or any process allowed to view that endpoint could see the secret in plaintext. Prometheus has patched the issue in versions 3.5.3 and 3.11.3.

Executive priority

Treat as a high-priority secrets exposure issue, especially in environments using Prometheus remote write to Azure AD. Prioritize upgrades and credential rotation where the configuration endpoint was accessible beyond a tightly trusted group.

Technical view

In Prometheus before 3.5.3 and in 3.6.0 through before 3.11.3, storage/remote/azuread remote write OAuth client_secret was typed as string instead of Secret. The /-/config endpoint redacts Secret fields, but not this string field, causing plaintext disclosure. CVSS is 7.5, driven by high confidentiality impact.

Likely exposure

Exposure is likely limited to Prometheus deployments using Azure AD remote write OAuth configuration and allowing access to the /-/config HTTP API endpoint. Risk increases if the endpoint is reachable by broad internal audiences, automation, dashboards, proxies, or the internet.

Exploitation context

No active exploitation is stated in the provided sources, and this CVE is not marked KEV in the bundle. Exploitation does not require complex interaction if an attacker already has network or process access to the configuration endpoint. The main impact is theft of the Azure OAuth client secret.

Researcher notes

The root cause is a type mismatch: client_secret was declared as string rather than Secret, bypassing Prometheus configuration redaction. Public sources identify fixed versions and related pull requests. Evidence does not establish real-world exploitation or affected downstream package status beyond cited vendor advisories.

Mitigation direction

  • Upgrade Prometheus to 3.5.3 or 3.11.3, as appropriate for your branch.
  • Restrict access to the /-/config endpoint to trusted administrators and systems only.
  • If exposure is plausible, rotate the affected Azure OAuth client secret.
  • Review vendor and distribution advisories for packaged Prometheus updates.

Validation and detection

  • Inventory Prometheus versions and identify deployments before 3.5.3 or 3.11.3.
  • Confirm whether storage/remote/azuread remote write OAuth is configured.
  • Verify who can access the /-/config HTTP API endpoint.
  • After upgrading, confirm the Azure client_secret is no longer shown in plaintext.
  • Review endpoint access logs for unexpected /-/config access.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · medium confidence lookup

CWE-200: Information exposure and cloud metadata lookup

Information exposure and SSRF weaknesses can make discovery, cloud metadata, and credential material review relevant. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cwe · low confidence lookup

CWE-256: Exact CWE lookup

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cwe · low confidence lookup

CWE-312: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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description · low confidence lookup

Database behavior lookup

The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-42151 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
20Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6GitHub_M
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N3.93.6redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-42151Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPgithub.com/prometheus/prometheus: Prometheus: Information disclosure of Azure OAuth client secret via config API
other:Red Hat severity ratingcvssV3_1
  • 2026-05-04T19:02:26.983Z: Reported to Red Hat.
  • 2026-05-04T18:12:16.917Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
prometheusprometheus< 3.5.3, >= 3.6.0, < 3.11.3Listed
Weakness

CWE details

CWE-200CWE-256CWE-312

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.