Path Traversal in Grafana Enterprise Metrics (Gem)
CVE-2026-81938
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- grafana.com/security/security-advisories/cve-2026-81938 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-81938?
- CVE-2026-81938 is a high-severity vulnerability in Grafana Enterprise Metrics (Gem), classified under Path Traversal. CVSS score: 7.7/10. Published 2026-11-02.
- How severe is CVE-2026-81938?
- High severity. CVSS v3 base score is 7.7 out of 10.