CVE-2026-9703

Viewer role can create, modify and delete Loki alerting rules

State: Published
Severity: 7.1 High
Published: Oct 15, 2026
Updated: Oct 16, 2026
Reserved: May 27, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L	GRAFANA

Weaknesses

CWE-284

Affected Products

Product	Versions
Grafana EnterpriseGrafana	8.0.0 through 11.5.10Affected 11.6.0 through 11.6.16Affected 12.0.0 through 12.1.10Affected 12.2.0 through 12.2.10Affected 12.3.0 through 12.3.8Affected 12.4.0 through 12.4.5Affected 13.0.0 through 13.0.3Affected
Grafana OSSGrafana	12.3.0 through 12.3.8Affected 12.4.0 through 12.4.5Affected 8.0.0 through 12.3.0Affected 13.0.0 through 13.0.3Affected

References

https://grafana.com/security/security-advisories/cve-2026-9703vendor-advisory

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