CVE-2026-81938VulnerabilityPublished 2 Nov 2026

Grafana Mimir's Alertmanager rejects tenant-supplied receiver configurations that reference local files, but the check

Source GCVE Database

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Authoritative record:CVE-2026-81938· High 7.7

Not known to be exploited · CVSS 7.7 High : upgrade to 3.2.2 or 3.1.7 soon.

Data as of 2 Nov 2026, 23:28 UTC

CVSS 3.1 base score

7.7High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (GRAFANA)	CVSS 3.1	7.7

Patch: Available – fixed in 2.17.20, 3.2.2, 3.1.7

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 2 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-243g-h4f6-prqr

What to do

Upgrade Grafana Mimir to 3.2.2 or 3.1.7; Enterprise Metrics (GEM) to 2.17.20.

Affected software

Product	Affected	Fixed in
GrafanaEnterprise Metrics (GEM)	Affected >=2.11.0 <=2.16.2 >=2.17.0 <2.17.20	Fixed in 2.17.20
GrafanaGrafana Mimir	Affected >=3.2.0 <3.2.2	Fixed in 3.2.2
GrafanaGrafana Mimir	Affected >=3.0.4 <3.1.7	Fixed in 3.1.7

AI-suggested

Upgrade to Grafana Mimir versions 3.1.7 or 3.2.2 or later. For Grafana Enterprise Metrics (GEM), upgrade to version 2.17.20 or later. Versions 2.11 through 2.16 of GEM will not receive fixes and should be upgraded. No other mitigations are indicated. Users without permission to upload tenant Alertmanager configurations are not affected.

Description

Grafana Mimir's Alertmanager contains a vulnerability where tenant-supplied Alertmanager configurations can reference local files via certain HTTP client settings not properly checked. This allows a tenant with configuration write permissions to read arbitrary files on the Alertmanager host by including their contents in outgoing request headers. The issue affects Grafana Mimir and Grafana Enterprise Metrics (GEM). Fixed versions are Mimir 3.1.7 and 3.2.2, and GEM 2.17.20 and later. Older GEM versions 2.11 through 2.16 will not receive fixes and require upgrading.

Impact

An attacker with permission to upload tenant Alertmanager configurations can read arbitrary files on the Alertmanager host by exploiting insufficient validation of certain HTTP client settings. This can lead to disclosure of sensitive information such as credentials and configuration files. The vulnerability has a high severity CVSS score of 7.7, indicating significant confidentiality impact without integrity or availability impact.

CWE-22Improper Limitation of a Pathname to a Restricted Directory (Path Traversal) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #6OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Path Traversal (opens in a new tab)
Using Slashes and URL Encoding Combined to Bypass Validation Logic (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
Using Escaped Slashes in Alternate Encoding (opens in a new tab)
Using Slashes in Alternate Encoding (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 2 Nov 2026, 23:28 UTC

WeaknessesCWE-22

Technical details

References

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