Vulnerability-Lookup

GHSA-8QQ9-CQJ8-82W4

Vulnerability from github – Published: 2026-06-12 18:31 – Updated: 2026-08-24 21:45

Summary

Mattermost doesn't sanitize FileInfo.Name received from federated peers during shared channel file sync

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 sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field. Mattermost Advisory ID: MMSA-2026-00661

Severity

7.6 (High)


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

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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": "8.0.0-20260423180926-c021eeaff8f0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-6961"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-24T21:45:51Z",
    "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 sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server\u0027s filestore via path traversal sequences in the filename field. Mattermost Advisory ID: MMSA-2026-00661",
  "id": "GHSA-8qq9-cqj8-82w4",
  "modified": "2026-08-24T21:45:52Z",
  "published": "2026-06-12T18:31:59Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6961"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36255"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36253"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36252"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36251"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/pull/36223"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/c896a63dc44c2f9c081a0a15bfddc4e6eb50e753"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/c021eeaff8f003034ab40f82c552cc26a710a8fd"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/a9f3868e1eee9ec61855cd7277f39937385efffd"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/a0056ed68d95f64d7c4586985e7b7f16b96b3bec"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mattermost/mattermost/commit/61d68d2d6ee81a5919597d91c736c502d7156859"
    },
    {
      "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:H/UI:N/S:C/C:N/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost doesn\u0027t sanitize FileInfo.Name received from federated peers during shared channel file sync"
}

CVE-2026-6961 (GCVE-0-2026-6961)

Vulnerability from cvelistv5 – Published: 2026-06-12 15:56 – Updated: 2026-06-16 13:17

Title

CVE-2026-6961: Path traversal via unsanitized FileInfo.Name in Mattermost federation sync

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 sanitize FileInfo.Name received from federated peers during shared channel file sync, which allows an attacker who controls a federated server to write files to arbitrary locations within the target server's filestore via path traversal sequences in the filename field.. Mattermost Advisory ID: MMSA-2026-00661

Severity

7.6 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-13 03:56 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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

Hassan Mohammed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
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        "metrics": [
          {
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              "content": {
                "id": "CVE-2026-6961",
                "options": [
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                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-13T03:56:08.575775Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
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        "providerMetadata": {
          "dateUpdated": "2026-06-16T13:17:18.192Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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              "versionType": "semver"
            },
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              "lessThanOrEqual": "10.11.15",
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              "version": "10.11.0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "10.11.16",
              "status": "affected",
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              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.7.0"
            },
            {
              "status": "unaffected",
              "version": "11.6.2"
            },
            {
              "status": "unaffected",
              "version": "11.5.5"
            },
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              "status": "unaffected",
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        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "LOW",
            "baseScore": 7.6,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "userInteraction": "NONE",
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        ],
        "discovery": "{\"self\"=\u003e\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=\u003e\"Internal\", \"id\"=\u003e\"10557\"}"
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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.

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GHSA-8QQ9-CQJ8-82W4

CVE-2026-6961 (GCVE-0-2026-6961)

Tags

Sightings

Nomenclature