Vulnerability-Lookup

GHSA-VPH7-R229-QXPF

Vulnerability from github – Published: 2026-04-03 15:30 – Updated: 2026-04-06 15:08

Summary

Focalboard doesn't validate file ownership when serving uploaded files

Details

** 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.

Severity

4.3 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/mattermost/focalboard"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "7.10.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-28736"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-639"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-06T15:08:47Z",
    "nvd_published_at": "2026-04-03T14:16:29Z",
    "severity": "MODERATE"
  },
  "details": "** 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\u0027s fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued.",
  "id": "GHSA-vph7-r229-qxpf",
  "modified": "2026-04-06T15:08:47Z",
  "published": "2026-04-03T15:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-28736"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mattermost-community/focalboard"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Focalboard doesn\u0027t validate file ownership when serving uploaded files"
}

CVE-2026-28736 (GCVE-0-2026-28736)

Vulnerability from cvelistv5 – Published: 2026-04-03 13:25 – Updated: 2026-04-03 14:54 Unsupported When Assigned

Title

Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)

Summary

Severity

4.3 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-03 14:53 UTC

CWE

CWE-639 - Authorization Bypass Through User-Controlled Key

Assigner

Mattermost mitre root Scorecard

References

1 reference

URL	Tags
https://github.com/mattermost-community/focalboard	product

Impacted products

1 product

Vendor	Product	Version
Mattermost	Focalboard	Affected: 0 , ≤ 8.0 (semver)

Credits

Siam Thanat Hack Company Limited

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-28736",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-03T14:53:54.422014Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-03T14:54:37.869Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Focalboard",
          "vendor": "Mattermost",
          "versions": [
            {
              "lessThanOrEqual": "8.0",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Siam Thanat Hack Company Limited"
        }
      ],
      "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\u0027s fileID to read the content of the file. NOTE: Focalboard as a standalone product is not maintained and no fix will be issued."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 4.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-639",
              "description": "CWE-639: Authorization Bypass Through User-Controlled Key",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-03T13:25:53.399Z",
        "orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
        "shortName": "Mattermost"
      },
      "references": [
        {
          "name": "Focalboard Repository (Unmaintained)",
          "tags": [
            "product"
          ],
          "url": "https://github.com/mattermost-community/focalboard"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "tags": [
        "unsupported-when-assigned"
      ],
      "title": "Focalboard IDOR in file content endpoint allows cross-user file access (unsupported product, no fix)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee",
    "assignerShortName": "Mattermost",
    "cveId": "CVE-2026-28736",
    "datePublished": "2026-04-03T13:25:53.399Z",
    "dateReserved": "2026-04-03T13:10:59.177Z",
    "dateUpdated": "2026-04-03T14:54:37.869Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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GHSA-VPH7-R229-QXPF

CVE-2026-28736 (GCVE-0-2026-28736)

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