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Medium

Admin RCE via Malicious Plugin Upload on CI Test Instances

Type: advisorySources: OSV

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-2462
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 10:23 UTC · Revision 1

Source evidence

Admin RCE via Malicious Plugin Upload on CI Test Instances

core-osv · Original source

Published 16 Mar 2026, 12:00 UTC

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528

osv:CVE-2026-2462
Complete source record
{
  "id": "62a9226d001d19305035338c072300f5021eb32d930fb64f1f6ca4872af39303",
  "url": "https://osv.dev/vulnerability/CVE-2026-2462",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Admin RCE via Malicious Plugin Upload on CI Test Instances",
    "summary": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to restrict plugin installation on CI test instances with default admin credentials which allows an unauthenticated attacker to achieve remote code execution and exfiltrate sensitive configuration data including AWS and SMTP credentials via uploading a malicious plugin after changing the import directory. Mattermost Advisory ID: MMSA-2025-00528",
    "evidence": "osv:CVE-2026-2462",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-2462",
      "aliases": [
        "CVE-2026-2462"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mattermost/mattermost",
              "type": "GIT",
              "events": [
                {
                  "introduced": "5b955468ea1ea8b56c0fb10feb258a36a767d7bb"
                },
                {
                  "fixed": "fddd4a70bcb32eaff394a2fa5399efcd1b2ae251"
                },
                {
                  "introduced": "ab7b138824c61fe1fe815243d7e2a914dec49c8b"
                },
                {
                  "fixed": "005521aa79666e6960bc3302f6172b810f6bff3a"
                },
                {
                  "introduced": "d27a2195068ddfa3ce17cf470f9739e4edb94b83"
                },
                {
                  "fixed": "4082c3dcf285e4d1a386d2ef37f14f39dc5a0094"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "10.11.0"
                      },
                      {
                        "fixed": "10.11.11"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "11.2.0"
                      },
                      {
                        "fixed": "11.2.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "11.3.0"
                      },
                      {
                        "fixed": "11.3.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v10.11.11-rc1",
            "v11.3.1-rc1",
            "v10.11.10",
            "v11.2.2",
            "v11.3.0-rc4",
            "v11.3.0-rc3",
            "v11.3.0",
            "mattermost-redux@11.3.0",
            "@mattermost/types@11.3.0",
            "@mattermost/client@11.3.0",
            "v10.11.9",
            "v11.2.1",
            "v11.2.1-rc1",
            "v11.2.0",
            "v10.11.9-rc1",
            "v10.11.8",
            "v10.11.7",
            "v10.11.6",
            "v10.11.5",
            "v10.11.4-rc3",
            "v10.11.4",
            "v10.11.4-rc2",
            "v10.11.4-rc1",
            "v10.11.3",
            "v10.11.2-rc2",
            "v10.11.2",
            "v10.11.2-rc1",
            "v10.11.1",
            "v10.11.1-rc1",
            "v10.11.0-rc3",
            "v10.11.0",
            "mattermost-redux@10.11.0",
            "@mattermost/types@10.11.0",
            "@mattermost/client@10.11.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-2462.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.742321797Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2462.json",
        "https://mattermost.com/security-updates",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-2462"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-863"
        ],
        "cna_assigner": "Mattermost",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "11.3.0"
                  },
                  {
                    "last_affected": "11.3.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandaloneSingleVersion"
              }
            ]
          },
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "11.2.0"
                  },
                  {
                    "last_affected": "11.2.2"
                  },
                  {
                    "introduced": "10.11.0"
                  },
                  {
                    "last_affected": "10.11.10"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/2xxx/CVE-2026-2462.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-2462",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494460,
  "published_at": "2026-03-16T12:00:21.069+00:00"
}