Grafana Data Source Proxy /loki/api/v1/rules access control

Summaryinfo

A vulnerability was found in Grafana. It has been rated as problematic. Affected by this vulnerability is an unknown functionality of the file /loki/api/v1/rules of the component Data Source Proxy. Performing a manipulation results in access control. This vulnerability is identified as CVE-2026-9703. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic has been found in Grafana (version unknown). This affects an unknown function of the file /loki/api/v1/rules of the component Data Source Proxy. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at grafana.com. This vulnerability is uniquely identified as CVE-2026-9703 since 05/27/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/15/2026). The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• Grafana

License

• open-source

CPE 2.3info

• 🔒

CPE 2.2info

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