GHSA-3VCM-C42P-3HHF

Vulnerability from github – Published: 2025-09-15 12:31 – Updated: 2025-09-15 20:38
VLAI?
Summary
Mattermost Missing Authorization vulnerability
Details

Mattermost versions 10.10.x <= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects Mattermost Server instances with shared channels enabled.

Severity ?
6.5 (Medium)
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost/server/v8"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.0.0-20250729073403-517ae758cd02"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/mattermost-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "10.10.0"
            },
            {
              "fixed": "10.10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-9076"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-09-15T20:38:31Z",
    "nvd_published_at": "2025-09-15T10:15:32Z",
    "severity": "MODERATE"
  },
  "details": "Mattermost versions 10.10.x \u003c= 10.10.1 fail to properly sanitize user data during shared channel membership synchronization, which allows malicious or compromised remote clusters to access sensitive user information via unsanitized user objects. This vulnerability affects Mattermost Server instances with shared channels enabled.",
  "id": "GHSA-3vcm-c42p-3hhf",
  "modified": "2025-09-15T20:38:31Z",
  "published": "2025-09-15T12:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-9076"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost/mattermost"
    },
    {
      "type": "WEB",
      "url": "https://mattermost.com/security-updates"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Mattermost Missing Authorization vulnerability"
}


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  • 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.