Parse Server before 8.6.93 and 9.0.0 before 9.10.1 protectedFields Bypass via Relation Count Query

{
  "id": "df51120a29ff9688a33360a7fa1e21a9e845ef93af3024714ce34c77a1ae529e",
  "url": "https://osv.dev/vulnerability/BIT-parse-2026-109303",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Parse Server before 8.6.93 and 9.0.0 before 9.10.1 protectedFields Bypass via Relation Count Query",
    "summary": "Parse Server before 8.6.93 and 9.0.0 before 9.10.1 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.",
    "evidence": "osv:BIT-parse-2026-109303",
    "products": [
      {
        "name": {
          "value": "parse",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "8.6.93",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "9.10.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "BIT-parse-2026-109303",
      "aliases": [
        "BIT-parse-2026-109303",
        "CVE-2026-109303",
        "GHSA-rmhf-xv62-rm99"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "8.6.93"
                },
                {
                  "introduced": "9.0.0"
                },
                {
                  "fixed": "9.10.1"
                }
              ]
            }
          ],
          "package": {
            "name": "parse",
            "purl": "pkg:bitnami/parse",
            "ecosystem": "Bitnami"
          },
          "severity": [
            {
              "type": "CVSS_V4",
              "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
            }
          ],
          "database_specific": {
            "source": "https://github.com/bitnami/vulndb/tree/main/data/parse/BIT-parse-2026-109303.json"
          }
        }
      ],
      "modified": "2026-10-19T15:10:40.564054594Z",
      "provider": "osv",
      "references": [
        "https://github.com/parse-community/parse-server/security/advisories/GHSA-rmhf-xv62-rm99",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-109303",
        "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"
      ],
      "provider_metadata": {
        "cpes": [
          "cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:*"
        ],
        "severity": "Medium"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-109303",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 375268,
  "published_at": "2026-10-19T14:26:34.738+00:00"
}