Vulnerability-Lookup

GHSA-243G-H4F6-PRQR

Vulnerability from github – Published: 2026-11-02 21:31 – Updated: 2026-11-02 21:31

Details

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.

Severity

7.7 (High)


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

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-81938"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-02T19:18:11Z",
    "severity": "HIGH"
  },
  "details": "Grafana Mimir\u0027s Alertmanager rejects tenant-supplied receiver configurations that reference local files, but the check did not cover two HTTP client settings: http_headers.\u003cname\u003e.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.\n\nExploitation requires permission to write the tenant\u0027s 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.",
  "id": "GHSA-243g-h4f6-prqr",
  "modified": "2026-11-02T21:31:58Z",
  "published": "2026-11-02T21:31:58Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81938"
    },
    {
      "type": "WEB",
      "url": "https://grafana.com/security/security-advisories/cve-2026-81938"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-81938 (GCVE-0-2026-81938)

Vulnerability from cvelistv5 – Published: 2026-11-02 18:23 – Updated: 2026-11-02 19:06

Title

Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir

Summary

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.

Severity

7.7 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-11-02 19:06 UTC

CWE

CWE-22

Assigner

GRAFANA CNA under the mitre root

CNA scorecard C 71/100 over 55 records in the last 180 days details

References

1 reference

URL	Tags
https://grafana.com/security/security-advisories/…	vendor-advisory

Impacted products

2 products

Vendor	Product	Version
Grafana	Enterprise Metrics (GEM)	Affected: 2.11.0 , ≤ 2.16.2 (semver) Affected: 2.17.0 , < 2.17.20 (semver)
Grafana	Grafana Mimir	Affected: 3.0.4 , < 3.1.7 (semver) Affected: 3.2.0 , < 3.2.2 (semver)

Date Public

2026-09-27 19:29

Credits

arang

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-81938",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-11-02T19:06:44.198911Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-11-02T19:06:58.641Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Enterprise Metrics (GEM)",
          "vendor": "Grafana",
          "versions": [
            {
              "lessThanOrEqual": "2.16.2",
              "status": "affected",
              "version": "2.11.0",
              "versionType": "semver"
            },
            {
              "lessThan": "2.17.20",
              "status": "affected",
              "version": "2.17.0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Grafana Mimir",
          "vendor": "Grafana",
          "versions": [
            {
              "lessThan": "3.1.7",
              "status": "affected",
              "version": "3.0.4",
              "versionType": "semver"
            },
            {
              "lessThan": "3.2.2",
              "status": "affected",
              "version": "3.2.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "arang"
        }
      ],
      "datePublic": "2026-09-27T19:29:04.693Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "Grafana Mimir\u0027s Alertmanager rejects tenant-supplied receiver configurations that reference local files, but the check did not cover two HTTP client settings: http_headers.\u003cname\u003e.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.\n\nExploitation requires permission to write the tenant\u0027s 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-02T18:23:43.604Z",
        "orgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da",
        "shortName": "GRAFANA"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://grafana.com/security/security-advisories/cve-2026-81938"
        }
      ],
      "source": {
        "discovery": "BUG_BOUNTY"
      },
      "title": "Arbitrary file read via Alertmanager receiver configuration in Grafana Mimir"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da",
    "assignerShortName": "GRAFANA",
    "cveId": "CVE-2026-81938",
    "datePublished": "2026-11-02T18:23:43.604Z",
    "dateReserved": "2026-08-27T19:29:04.581Z",
    "dateUpdated": "2026-11-02T19:06:58.641Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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