CVE-2026-28736

{
  "id": "CVE-2026-28736",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-03T14:16:29.517",
  "lastModified": "2026-10-23T22:10:00.160",
  "vulnStatus": "Analyzed",
  "cveTags": [
    {
      "sourceIdentifier": "[email protected]",
      "tags": [
        "unsupported-when-assigned"
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "** UNSUPPORTED WHEN ASSIGNED ** Focalboard version 8.0 fails to validate file ownership when serving uploaded files. This allows an authenticated attacker who knows a victim's fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued."
    },
    {
      "lang": "es",
      "value": "NO COMPATIBLE CUANDO ASIGNADO  La versión 8.0 de Focalboard no valida la propiedad de los archivos al servir archivos subidos. Esto permite a un atacante autenticado que conoce el ID de archivo de una víctima leer el contenido del archivo. NOTA: Focalboard como producto independiente no recibe mantenimiento y no se emitirá ninguna corrección."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Mattermost",
          "product": "Focalboard",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0",
              "lessThanOrEqual": "8.0",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-03T14:53:54.422014Z",
          "id": "CVE-2026-28736",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-639"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:mattermost:focalboard:8.0.0:*:*:*:*:*:*:*",
              "matchCriteriaId": "42087E46-C9CC-46D7-B424-55537457FE0A"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/mattermost-community/focalboard",
      "source": "[email protected]",
      "tags": [
        "Product"
      ]
    }
  ]
}