Vulnerability-Lookup

GHSA-6HXM-W4HV-VGVW

Vulnerability from github – Published: 2026-06-12 18:31 – Updated: 2026-08-24 21:51

Summary

Mattermost doesn't require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints

Details

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 fail to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests. Mattermost Advisory ID: MMSA-2026-00665

Severity

8.8 (High)


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

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.6.0"
            },
            {
              "fixed": "11.6.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "11.6.0"
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 11.5.4"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "11.5.0"
            },
            {
              "fixed": "11.5.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 10.11.15"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.11.0"
            },
            {
              "fixed": "10.11.17"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0-20250731163400-5b955468ea1e"
            },
            {
              "fixed": "8.0.0-20260506065351-202d125afa87"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-7387"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-24T21:51:47Z",
    "nvd_published_at": "2026-06-12T17:16:27Z",
    "severity": "HIGH"
  },
  "details": "Mattermost versions 11.6.x \u003c= 11.6.1, 11.5.x \u003c= 11.5.4, 10.11.x \u003c= 10.11.15, 10.11.x \u003c= 10.11.16 fail to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests. Mattermost Advisory ID: MMSA-2026-00665",
  "id": "GHSA-6hxm-w4hv-vgvw",
  "modified": "2026-08-24T21:51:47Z",
  "published": "2026-06-12T18:31:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-7387"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36434"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36432"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36431"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36423"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36316"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/d5f29c8ebbeb04460d16d9e2635ce50deeb78428"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/a9e574a82633915f22071f0d7ca2b006f249ec2a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/8c72083414e675c97987374395e36d1f36b4bd8a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/202d125afa87fe39611686850fd82590c99ca344"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/1ce2484a00c9821ee19708d2c46720e4855033a9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/releases/tag/v10.11.16"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/releases/tag/v11.5.5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/releases/tag/v11.6.2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/releases/tag/v11.7.0"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost doesn\u0027t require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints"
}

CVE-2026-7387 (GCVE-0-2026-7387)

Vulnerability from cvelistv5 – Published: 2026-06-12 15:54 – Updated: 2026-06-13 03:56

Title

Mattermost group syncable endpoints allow privilege escalation via scheme_admin

Summary

Mattermost versions 11.6.x <= 11.6.1, 11.5.x <= 11.5.4, 10.11.x <= 10.11.15, 10.11.x <= 10.11.16 Mattermost fails to require role-management authorization when setting the scheme_admin flag on group syncable link and patch endpoints, which allows a user with group-link permissions to escalate themselves and group members to team or channel admin via crafted API requests.. Mattermost Advisory ID: MMSA-2026-00665

Severity

8.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-12 00:00 UTC

CWE

CWE-863 - Incorrect Authorization

Assigner

Mattermost mitre root

References

1 reference

URL	Tags
https://mattermost.com/security-updates	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
Mattermost	Mattermost	Affected: 11.6.0 , ≤ 11.6.1 (semver) Affected: 11.5.0 , ≤ 11.5.4 (semver) Affected: 10.11.0 , ≤ 10.11.15 (semver) Affected: 10.11.0 , ≤ 10.11.16 (semver) Unaffected: 11.7.0 Unaffected: 11.6.2 Unaffected: 11.5.5 Unaffected: 10.11.16 Unaffected: 10.11.17

Credits

winfunc

Show details on NVD website

JSON

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{
  "containers": {
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      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-7387",
                "options": [
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                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-12T00:00:00+00:00",
                "version": "2.0.3"
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              "version": "11.6.0",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "11.5.4",
              "status": "affected",
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              "status": "affected",
              "version": "10.11.0",
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            },
            {
              "lessThanOrEqual": "10.11.16",
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              "version": "11.7.0"
            },
            {
              "status": "unaffected",
              "version": "11.6.2"
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            {
              "status": "unaffected",
              "version": "11.5.5"
            },
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
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  },
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}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

GHSA-6HXM-W4HV-VGVW

CVE-2026-7387 (GCVE-0-2026-7387)

Tags

Sightings

Nomenclature