Collapsed Reply Threads APIs leak message contents from private channels

{
  "id": "c4b43eff61792c435a4520307873416793246c5a03e4ad438a48607dae8c5fc4",
  "url": "https://osv.dev/vulnerability/CVE-2023-2787",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Collapsed Reply Threads APIs leak message contents from private channels",
    "summary": "Mattermost fails to check channel membership when accessing message threads, allowing an attacker to access arbitrary posts by using the message threads API.",
    "evidence": "osv:CVE-2023-2787",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2023-2787",
      "aliases": [
        "CVE-2023-2787"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mattermost/mattermost",
              "type": "GIT",
              "events": [
                {
                  "introduced": "25e8c1fcddb1154de49480eb5cd7eb085507d138"
                },
                {
                  "last_affected": "96cf6c0f7a0c2e98815dbd9397c8de79528ae306"
                },
                {
                  "introduced": "f14c24391ca84740d90a29ec8b67579326eaa236"
                },
                {
                  "last_affected": "b3eb2e451e18b4003634954c2c4be678695dc26a"
                },
                {
                  "introduced": "c4d8c1450ab2b9538bbc2690ca1ee865567a5888"
                },
                {
                  "last_affected": "27b2437e0f93d3f48b9caebdceb7795b64d5cd9f"
                },
                {
                  "introduced": "5b33575d571469115f29720530ff5b53a6cb7de5"
                },
                {
                  "last_affected": "5b33575d571469115f29720530ff5b53a6cb7de5"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "7.1.0"
                      },
                      {
                        "last_affected": "7.1.9"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "7.8.0"
                      },
                      {
                        "last_affected": "7.8.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "7.9.0"
                      },
                      {
                        "last_affected": "7.9.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:mattermost:mattermost:7.10.0:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "7.10.0"
                      },
                      {
                        "last_affected": "7.10.0"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "7.10.0",
            "v7.9.3",
            "v7.1.9",
            "v7.8.4",
            "v7.10.0",
            "v7.9.2",
            "v7.8.3",
            "v7.1.8",
            "v7.9.1",
            "v7.8.2",
            "v7.1.7",
            "v7.9.0",
            "v7.8.1",
            "v7.1.6",
            "v7.8.0",
            "v7.1.5",
            "v7.1.4",
            "v7.1.3",
            "v7.1.2",
            "v7.1.1",
            "v7.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-2787.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.679926230Z",
      "provider": "osv",
      "references": [
        "https://mattermost.com/security-updates/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/2xxx/CVE-2023-2787.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-2787"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-862"
        ],
        "cna_assigner": "Mattermost",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "7.10.0"
                  },
                  {
                    "last_affected": "7.10.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandaloneSingleVersion"
              }
            ]
          },
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "last_affected": "7.9.3"
                  },
                  {
                    "last_affected": "7.8.4"
                  },
                  {
                    "last_affected": "7.1.9"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/2xxx/CVE-2023-2787.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-2787",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 499759,
  "published_at": "2023-06-16T08:55:39.391+00:00"
}