Loki DatasourceApplication · Grafana
CVE-2026-42129
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA user with Viewer permissions can use a path traversal in the Loki data source plugin to reach administrative Loki endpoints and read sensitive backend configuration and internal service information.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA path traversal vulnerability in the Loki data source plugin allows users with Viewer-level permissions to bypass intended access restrictions and traverse paths to reach administrative Loki endpoints, enabling unauthorized access to sensitive backend configuration files and internal service information.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Loki DatasourceApplication
all versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Loki datasource is enabledNavigate to Configuration > Data Sources in Grafana UI or query the /api/datasources API endpoint to list configured datasources. Look for 'Loki' in the datasource list.Affected if Loki datasource appears in the configured datasources list
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Identify Viewer-role users or service accountsNavigate to Configuration > Users and Teams in Grafana UI, or query the /api/users and /api/org/roles API endpoints. List all users assigned the Viewer role.Affected if Any user account with Viewer role exists in the system
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Check Viewer permission to Loki datasourceNavigate to Configuration > Data Sources > Loki > Permissions, or inspect the datasource JSON configuration for 'accessControl' or 'readOnly' settings. Verify if Viewer role is granted query or browse permissions.Affected if Viewer role has query, read, or browse permissions enabled on the Loki datasource
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Test path traversal access to Loki admin endpointsUsing an authenticated session as a Viewer user, attempt a curl request to a Loki administrative endpoint using path traversal sequences, such as: GET /api/datasources/uid/{loki-uid}/resources/../../admin/config or similar path patterns pointing to internal Loki endpoints.Affected if The request returns sensitive configuration data, backend service information, or administrative responses instead of being rejected with 403 Forbidden
Your environment is affected if the Loki datasource is enabled and Viewer-role users can query it, as the path traversal bypass allows them to access administrative endpoints.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply proper input validation and path sanitization in the Loki data source plugin to prevent path traversal sequences, and enforce strict permission checks ensuring Viewer users cannot access administrative endpoints.
Fix this in Loki Datasource
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42129 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42129 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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