Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir

Grafana Mimir's Alertmanager rejects tenant-supplied receiver configurations that reference local files, but the check did not cover two HTTP client settings: http_headers.<name>.files and basic_auth.username_file. A tenant permitted to upload an Alertmanager configuration could point these fields at any file readable by the Alertmanager process. When a notification was sent, Alertmanager read the file and put its contents in a header of the outgoing request. By directing the receiver at a server they control, the tenant could read files from the Alertmanager host, such as credentials and configuration. Exploitation requires permission to write the tenant's Alertmanager configuration. Grafana Enterprise Metrics (GEM), which is built on Mimir, is also affected. The issue is fixed in Mimir 3.1.7 and 3.2.2 and in GEM 2.17.20. GEM 2.11 through 2.16 will not receive a fix; users on those versions should upgrade to 2.17.20 or later.

Tempo TraceQL query with exemplar hint could result in unbounded memory usage

A TraceQL query in Grafana Tempo with a large exemplars hint value can cause the Tempo instance to allocate an excessive amount of memory, resulting in an out-of-memory crash. This could allow an authenticated user to trigger a denial of service against the Tempo service.

Access policy with access to all tenants and using label selectors has more access

A vulnerability in the label-based access control of Grafana Labs Grafana Enterprise Metrics allows an attacker more access than intended. If an access policy which has label selector restrictions also has been granted access to all tenants in the system, the label selector restrictions will not be applied when using this policy with the affected versions of the software. This issue affects: Grafana Labs Grafana Enterprise Metrics GEM 1.X versions prior to 1.7.1 on AMD64; GEM 2.X versions prior to 2.3.1 on AMD64.

The Alertmanager in Grafana Enterprise Metrics before 1.2.1 and Metrics Enterprise 1.2.1 has a local file disclosure vulnerability when experimental.alertmanager.enable-api is used. The HTTP basic auth password_file can be used as an attack vector to send any file content via a webhook. The alertmanager templates can be used as an attack vector to send any file content because the alertmanager can load any text file specified in the templates list.