Answer in brief
CVE-2026-81938 records a High severity (CVSS 7.7) vulnerability in Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir. The current sources do not mark it as known exploited. The current feed maps Grafana/Enterprise Metrics (GEM) (generic), Grafana/Grafana Mimir (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Grafana/Enterprise Metrics (GEM) (generic), Grafana/Grafana Mimir (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Grafana/Enterprise Metrics (GEM)generic | >=2.11.0 <=2.16.2 || >=2.17.0 <2.17.20 | 2.17.20 |
| Grafana/Grafana Mimirgeneric | >=3.0.4 <3.1.7 || >=3.2.0 <3.2.2 | 3.1.7, 3.2.2 |
Published upstream
Nov 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 2, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 2, 2026
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.
Quoted source text, attributed separately from HOL analysis.