{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "parse-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.0.0"
            },
            {
              "fixed": "9.9.1-alpha.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "parse-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.6.77"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-47138"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-23T00:11:25Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact\n\nAn unauthenticated attacker who knows a publicly-known Parse Application ID can submit a single HTTP request whose client SDK version field contains adversarial input that triggers polynomial backtracking in a request-header parser. The parsing runs before session authentication and before rate limiting on every `/parse/*` request, so the request consumes seconds to minutes of synchronous CPU on a Node.js worker before any access control evaluates it. A small number of concurrent requests can saturate a worker; a single large request via the body-field variant can pin a worker for minutes. Production deployments running the default configuration are affected.\n\n### Patches\n\nThe client SDK version capture and parsing have been removed entirely. The Parse JS SDK compatibility table defines a strict version-pinned contract between Parse Server and the Parse JS SDK; server-side adaptation to client SDK version is an obsolete pattern that contradicts that contract. The vulnerable parser, the `clientSDK` parameter that threaded its output through routers, and the legacy code path it gated are all removed. The `X-Parse-Client-Version` header and `_ClientVersion` JSON body field are now silently ignored on every request; supported Parse SDKs are unaffected.\n\n### Workarounds\n\nDeploy a reverse proxy or WAF in front of Parse Server that strips or strictly size-limits the `X-Parse-Client-Version` header AND the `_ClientVersion` field in JSON request bodies on every `/parse/*` route before forwarding to the server. A header-size cap alone is insufficient: the body-field variant requires inspection of JSON content. Upgrading to the patched version is the recommended remediation.",
  "id": "GHSA-38m6-82c8-4xfm",
  "modified": "2026-05-23T00:11:25Z",
  "published": "2026-05-23T00:11:25Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/security/advisories/GHSA-38m6-82c8-4xfm"
    },
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/pull/10463"
    },
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/pull/10464"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/parse-community/parse-server"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Parse Server: Pre-authentication denial of service via client version header regex backtracking"
}