This vulnerability in Grafana OSS occurs in the Unified Alerting component where an attacker with permission to create or edit alert rules in a folder can bypass datasource query permissions. By submitting an alert-rule query with queryType set to "__expr__" and specifying the UID of a real datasource, the authorization path incorrectly skips permission enforcement because it trusts the client-controlled queryType. However, during query evaluation, Grafana uses the datasource UID to execute the query with the datasource's credentials. This inconsistency between authorization and execution leads to unauthorized data access. The root cause is improper authorization logic that does not validate the relationship between queryType and datasource UID, allowing a low-privileged user to access data they should not query directly.

The vulnerability allows a low-privileged authenticated user to access data from datasources for which they lack query permissions, resulting in a high confidentiality impact. Integrity impact is low since some datasources may allow state-changing queries, but no availability impact has been demonstrated. The scope remains unchanged as the impact is confined within Grafana's security boundaries.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The recommended remediation includes not exempting queries from datasource authorization based solely on client-controlled queryType, resolving the referenced datasource server-side before authorization, enforcing datasources:query permission for real datasources, and ensuring authorization and evaluation use the same canonical datasource identity. Additionally, expression queries should only reference the canonical server-side expression datasource, rejecting mismatches. Regression tests should cover scenarios with folder-level alert-rule edit permission but without datasource query permission. Until a patch is released, restrict alert rule edit permissions to trusted users only.