CVE-2026-42151 is a high-severity (CVSS 7.5) Information Exposure vulnerability in github.com/prometheus/prometheus. A fix is available for github.com/prometheus/prometheus — see the affected versions and patch details below.
Prometheus Azure AD remote write OAuth client secret exposed via config API
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42151.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-42151 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 388,997 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/prometheus/prometheusReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/prometheus/prometheus | ≥ 0.45.2&&< 0.311.3 | 0.311.3go get github.com/prometheus/prometheus@v0.311.3 |
Affected Products
prometheusprometheusDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/prometheus/prometheus, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/prometheus/prometheus to 0.311.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42151 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This Important information disclosure flaw in Prometheus affects instances configured to use Azure AD remote write with OAuth authentication. The client secret, intended to be a secure credential, is exposed in plaintext through the `/-/config` HTTP API endpoint. This could allow an attacker with access to this…
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | opentelemetry-collector-0:0.152.1-1.el10_2 | RHSA-2026:34357 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | opentelemetry-collector-0:0.152.1-1.el10_0 | RHSA-2026:53413 |
| Red Hat Enterprise Linux 9 | opentelemetry-collector-0:0.152.1-1.el9_8 | RHSA-2026:34359 |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | opentelemetry-collector-0:0.152.1-1.el9_4 | RHSA-2026:53412 |
| Red Hat Enterprise Linux 9.6 Extended Update Support | opentelemetry-collector-0:0.152.1-1.el9_6 | RHSA-2026:53415 |
| RHEM 1.0 for RHEL 9 | flightctl-0:1.0.3-1.el9em | RHSA-2026:36796 |
| RHEM 1.1 for RHEL 10 | flightctl-0:1.1.3-1.el10em | RHSA-2026:41019 |
| Logging Subsystem for Red Hat OpenShift 6.0 | openshift-logging/loki-rhel9-operator:1785418915 | RHSA-2026:50843 |
Frequently Asked Questions
Is CVE-2026-42151 in your dependencies?
Find it across Go, including transitive dependencies.