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Leaked User IDs and Metadata of Deleted DMs

Type: advisorySources: OSV

Mattermost versions 9.11.x <= 9.11.6 fail to filter out DMs from the deleted channels endpoint which allows an attacker to infer user IDs and other metadata from deleted DMs if someone had manually marked DMs as deleted in the database.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2025-0503
Confirmed fixed CVEs
Not specified
Updated in this feed
7 Nov 2026, 10:21 UTC · Revision 1

Source evidence

Leaked User IDs and Metadata of Deleted DMs

core-osv · Original source

Published 14 Feb 2025, 17:52 UTC

Mattermost versions 9.11.x <= 9.11.6 fail to filter out DMs from the deleted channels endpoint which allows an attacker to infer user IDs and other metadata from deleted DMs if someone had manually marked DMs as deleted in the database.

osv:CVE-2025-0503
Complete source record
{
  "id": "8ddda45a90cb904b4777117942446370e7a678271977f56d53170ff697c15e2c",
  "url": "https://osv.dev/vulnerability/CVE-2025-0503",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Leaked User IDs and Metadata of Deleted DMs",
    "summary": "Mattermost versions 9.11.x <= 9.11.6 fail to filter out DMs from the deleted channels endpoint which allows an attacker to infer user IDs and other metadata from deleted DMs if someone had manually marked DMs as deleted in the database.",
    "evidence": "osv:CVE-2025-0503",
    "products": [],
    "severity": "low",
    "structured": {
      "id": "CVE-2025-0503",
      "aliases": [
        "CVE-2025-0503"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mattermost/mattermost",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0bc2ddd42375a75ab14e63f038165150d4f07659"
                },
                {
                  "fixed": "6519009694d3a09586df7632261b441238d91f74"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "9.11.0"
                      },
                      {
                        "fixed": "9.11.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v9.11.7-rc2",
            "v9.11.7-rc1",
            "v9.11.6",
            "v9.11.6-rc2",
            "v9.11.6-rc1",
            "v9.11.5",
            "v9.11.5-rc1",
            "v9.11.4",
            "v9.11.4-rc1",
            "v9.11.3",
            "v9.11.3-rc2",
            "v9.11.3-rc1",
            "v9.11.2",
            "v9.11.2-rc2",
            "v9.11.2-rc1",
            "v9.11.1-rc1",
            "v9.11.1",
            "v9.11.0-rc3",
            "v9.11.0",
            "@mattermost/types@9.11.0",
            "@mattermost/client@9.11.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-0503.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.354125331Z",
      "provider": "osv",
      "references": [
        "https://mattermost.com/security-updates",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/0xxx/CVE-2025-0503.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-0503"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-754"
        ],
        "cna_assigner": "Mattermost",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "9.11.0"
                  },
                  {
                    "last_affected": "9.11.6"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/0xxx/CVE-2025-0503.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-0503",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518990,
  "published_at": "2025-02-14T17:52:17.895+00:00"
}