CVE-2026-9703
Received Received - Intake

Role-Based Access Bypass in Grafana Data Source Proxy to Loki

Publication date: 2026-10-15

Last updated on: 2026-10-15

Assigner: Grafana Labs

Description
Grafana's data source proxy did not apply role-based access control to write requests forwarded to Loki data sources. A user holding only the Viewer role on an affected Grafana instance could send POST, PUT and DELETE requests through the proxy to the Loki rules API (/loki/api/v1/rules), allowing them to create, modify and delete Loki alerting rules. Because those rules are stored by Loki rather than by Grafana, the change took effect for every user of that Loki data source, not only for the Viewer who made the request. Exploitation requires an authenticated Viewer account on the Grafana instance and a configured Loki data source; no other privileges are needed. Both Grafana OSS and Grafana Enterprise are affected. The defect is in Grafana's data source proxy; Loki itself is not vulnerable and does not need to be patched.

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Meta Information

Published
2026-10-15
Last Modified
2026-10-15
Generated
2026-10-15
AI Q&A
2026-10-15
EPSS Evaluated
N/A
NVD
CVE-2026-9703
EUVD
EUVD-2026-102073

Affected Vendors & Products

Showing 11 associated CPEs
Vendor Product Version / Range
Grafana Grafana Enterprise 8.0.0
Grafana Grafana Enterprise 11.6.0
Grafana Grafana Enterprise 12.0.0
Grafana Grafana Enterprise 12.2.0
Grafana Grafana Enterprise 12.3.0
Grafana Grafana Enterprise 12.4.0
Grafana Grafana Enterprise 13.0.0
Grafana Grafana OSS 12.3.0
Grafana Grafana OSS 12.4.0
Grafana Grafana OSS 8.0.0
Grafana Grafana OSS 13.0.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-284 The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

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Executive Summary

This vulnerability in Grafana allows a user with only the Viewer role to send write requests (POST, PUT, DELETE) to the Loki rules API through Grafana's data source proxy. This bypasses role-based access control and lets the Viewer create, modify, or delete Loki alerting rules. Since rules are stored in Loki, these changes affect all users of that Loki data source, not just the Viewer who made the request.

Detection Guidance

Check Grafana logs for unauthorized POST, PUT, or DELETE requests to /loki/api/v1/rules. Monitor Loki alerting rules for unexpected changes or new rules created by non-admin users.

Impact Analysis

If you are a Grafana Viewer with access to a Loki data source, an attacker could exploit this to alter alerting rules in Loki. This could lead to false alerts, missed critical alerts, or unauthorized modifications to monitoring configurations, potentially disrupting operations or hiding important events.

Compliance Impact

This vulnerability could impact compliance by allowing unauthorized changes to alerting rules, which may affect monitoring and logging integrity. For GDPR, this could undermine data protection measures if alerts are tampered with. For HIPAA, it might compromise the integrity of monitoring systems required for compliance. Organizations must ensure proper access controls and monitoring to mitigate risks.

Mitigation Strategies

Upgrade Grafana to a fixed version (8.0.0 or later) or apply patches for versions 12.3.9, 12.4.6, and 13.0.4. Review and restrict Viewer role permissions until patched.

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