{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "9.0.0"
              },
              {
                "fixed": "9.10.1-alpha.13"
              },
              {
                "introduced": "0"
              },
              {
                "fixed": "8.6.93"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "532a461d30a6ed4457839f2caf5f30d5abf51a55"
            },
            {
              "fixed": "543a6c852822403812be845a050bfa94e472ba01"
            },
            {
              "introduced": "0"
            },
            {
              "fixed": "989531267f47181898bdaa438ff8b48c4d403dd2"
            }
          ],
          "repo": "https://github.com/parse-community/parse-server",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-rmhf-xv62-rm99"
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-639"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109303.json"
  },
  "details": "Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 does not enforce identity-scoped protectedFields (authenticated, role, or per-user groups) on count queries using the $relatedTo operator, exposing the size of protected Relation fields. An authenticated user who can read the owning object can combine counts with an objectId constraint as a membership oracle to reveal confidential memberships such as private groups or block lists.",
  "id": "CVE-2026-109303",
  "modified": "2026-10-14T02:30:34.294416740Z",
  "published": "2026-10-12T16:05:00.257Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109303.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/parse-community/parse-server/security/advisories/GHSA-rmhf-xv62-rm99"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-109303"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/parse-server-before-8.6.93-and-9.0.0-before-9.10.1-alpha.13-protectedfields-bypass-via-relation-count-query"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Parse Server before 8.6.93 and 9.0.0 before 9.10.1-alpha.13 protectedFields Bypass via Relation Count Query"
}