CVE-2026-81938— Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir

Quick assessment

Affected

Grafana Enterprise Metrics (GEM)

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Grafana Mimir 的 Alertmanager 会拒绝租户提供的、引用本地文件的接收器配置，但原有的检查机制未覆盖两个 HTTP 客户端设置：和。若租户被允许上传 Alertmanager 配置，则可将这些字段指向 Alertmanager 进程可读取的任意文件。当发送通知时，Alertmanager 会读取该文件并将其内容放入出站请求的 HTTP 请求头中。通过将接收器指向攻击者控制的服务器，租户即可读取 Alertmanager 主机上的文件，例如凭据和配置文件。利用此漏洞需要拥有写入租户 Al

CVSS 7.7 · High Updated Nov 03, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 4

Vendor	Product	Version Range	Status
Grafana	Enterprise Metrics (GEM)	`2.11.0≤ 2.16.2`	affected
		`2.17.0< 2.17.20`	affected
Grafana	Grafana Mimir	`3.0.4< 3.1.7`	affected
		`3.2.0< 3.2.2`	affected

Get alerts for future matching vulnerabilities Log in to subscribe

Vulnerability Information

Have questions about the vulnerability? See if Shenlong's analysis helps!

View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title

Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir

Source: CVE Program / CVE List V5

Vulnerability Description

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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Source: CVE Program / CVE List V5

Vulnerability Type

对路径名的限制不恰当(路径遍历)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
Grafana	Enterprise Metrics (GEM)	2.11.0 ~ 2.16.2	-
Grafana	Grafana Mimir	3.0.4 ~ 3.1.7	-

II. Public POCs for CVE-2026-81938

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-81938

请登录查看更多情报信息。

Other References for CVE-2026-81938 (1)

https://grafana.com/security/security-advisories/cve-2026-81938 vendor-advisory

https://www.cve.org/CVERecord?id=CVE-2026-81938

IV. Related Vulnerabilities

Same vendor: Grafana

Same weakness: CWE-22