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Parse Server 9.0.0 Authentication Bypass via Unverified Provider Identity

Type: advisorySources: OSV

Parse Server is an open-source backend server. In versions >= 9.0.0 < 9.10.1-alpha.10 and >= 8.0.2 < 8.6.91, the code-based authentication adapters (GitHub, Google Play Games, Instagram, LINE, LinkedIn, Microsoft, QQ, Spotify, WeChat, Weibo) verify the client's authorization code with the external provider on signup and on provider linking, but not when authentication data is supplied together with a username and password on the login endpoint. As a result, a low-privileged authenticated user can attach an arbitrary, unverified provider identity to their own account without the provider ever being contacted, spoofing an external identity toward application logic that trusts the linked provider ID. An attacker can also pre-hijack accounts: by claiming the provider ID of a victim who has not yet linked that provider, the victim's later legitimate sign-in with that provider resolves to the attacker's account. Only deployments configuring one of the affected code-based auth adapters are impacted. Versions 9.10.1-alpha.10 and 8.6.91 fix the issue by running the adapter's credential verification on the login and challenge endpoints and rejecting a provider identity already linked to another user. As a workaround, disable the affected code-based auth adapters.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-101042
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 05:07 UTC · Revision 1

Source evidence

Parse Server 9.0.0 Authentication Bypass via Unverified Provider Identity

core-osv · Original source

Published 27 Sept 2026, 16:28 UTC

Parse Server is an open-source backend server. In versions >= 9.0.0 < 9.10.1-alpha.10 and >= 8.0.2 < 8.6.91, the code-based authentication adapters (GitHub, Google Play Games, Instagram, LINE, LinkedIn, Microsoft, QQ, Spotify, WeChat, Weibo) verify the client's authorization code with the external provider on signup and on provider linking, but not when authentication data is supplied together with a username and password on the login endpoint. As a result, a low-privileged authenticated user can attach an arbitrary, unverified provider identity to their own account without the provider ever being contacted, spoofing an external identity toward application logic that trusts the linked provider ID. An attacker can also pre-hijack accounts: by claiming the provider ID of a victim who has not yet linked that provider, the victim's later legitimate sign-in with that provider resolves to the attacker's account. Only deployments configuring one of the affected code-based auth adapters are impacted. Versions 9.10.1-alpha.10 and 8.6.91 fix the issue by running the adapter's credential verification on the login and challenge endpoints and rejecting a provider identity already linked to another user. As a workaround, disable the affected code-based auth adapters.

osv:CVE-2026-101042
Complete source record
{
  "id": "f1c06e95dddb635ed544943b6c70822b1506ff399142cc905ae6d0ad2eea4e85",
  "url": "https://osv.dev/vulnerability/CVE-2026-101042",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Parse Server 9.0.0 Authentication Bypass via Unverified Provider Identity",
    "summary": "Parse Server is an open-source backend server. In versions >= 9.0.0 < 9.10.1-alpha.10 and >= 8.0.2 < 8.6.91, the code-based authentication adapters (GitHub, Google Play Games, Instagram, LINE, LinkedIn, Microsoft, QQ, Spotify, WeChat, Weibo) verify the client's authorization code with the external provider on signup and on provider linking, but not when authentication data is supplied together with a username and password on the login endpoint. As a result, a low-privileged authenticated user can attach an arbitrary, unverified provider identity to their own account without the provider ever being contacted, spoofing an external identity toward application logic that trusts the linked provider ID. An attacker can also pre-hijack accounts: by claiming the provider ID of a victim who has not yet linked that provider, the victim's later legitimate sign-in with that provider resolves to the attacker's account. Only deployments configuring one of the affected code-based auth adapters are impacted. Versions 9.10.1-alpha.10 and 8.6.91 fix the issue by running the adapter's credential verification on the login and challenge endpoints and rejecting a provider identity already linked to another user. As a workaround, disable the affected code-based auth adapters.",
    "evidence": "osv:CVE-2026-101042",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-101042",
      "aliases": [
        "BIT-parse-2026-101042",
        "CVE-2026-101042",
        "GHSA-mr43-w6c2-mvjq"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/parse-community/parse-server",
              "type": "GIT",
              "events": [
                {
                  "introduced": "532a461d30a6ed4457839f2caf5f30d5abf51a55"
                },
                {
                  "fixed": "6d92204b554154eaef395e513da8324984b25ebb"
                },
                {
                  "introduced": "f20e0f3ccd6d4256b41f8bd21edf77fda3435d2e"
                },
                {
                  "fixed": "2475a26df72f98527e41622d4902bcaa8e5f7c54"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "9.0.0"
                      },
                      {
                        "fixed": "9.10.1-alpha.10"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "8.0.2"
                      },
                      {
                        "fixed": "8.6.91"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "9.10.0",
            "8.6.90",
            "9.10.1-alpha.9",
            "8.6.89",
            "9.10.1-alpha.8",
            "8.6.88",
            "9.10.1-alpha.7",
            "8.6.87",
            "9.10.1-alpha.6",
            "9.10.1-alpha.5",
            "9.10.1-alpha.4",
            "9.10.1-alpha.3",
            "9.10.1-alpha.2",
            "9.10.1-alpha.1",
            "9.9.0",
            "8.6.86",
            "8.6.85",
            "8.6.84",
            "8.6.83",
            "8.6.82",
            "8.6.81",
            "8.6.80",
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            "8.6.78",
            "8.6.77",
            "8.6.76",
            "9.8.0",
            "8.6.75",
            "9.7.0",
            "8.6.74",
            "8.6.73",
            "8.6.72",
            "8.6.71",
            "8.6.70",
            "9.6.1",
            "8.6.69",
            "8.6.68",
            "8.6.67",
            "8.6.66",
            "8.6.65",
            "8.6.64",
            "8.6.63",
            "8.6.62",
            "9.6.0",
            "9.5.1",
            "8.6.61",
            "8.6.60",
            "8.6.59",
            "8.6.58",
            "8.6.57",
            "8.6.56",
            "8.6.55",
            "8.6.54",
            "8.6.53",
            "8.6.52",
            "8.6.51",
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            "8.6.49",
            "8.6.48",
            "8.6.47",
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            "8.6.43",
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            "8.6.14",
            "8.6.13",
            "9.5.0",
            "8.6.12",
            "8.6.11",
            "9.4.1",
            "8.6.10",
            "8.6.9",
            "8.6.8",
            "8.6.7",
            "8.6.6",
            "8.6.5",
            "8.6.4",
            "9.4.0",
            "8.6.3",
            "9.3.1",
            "9.3.0",
            "8.6.2",
            "9.2.0",
            "9.1.1",
            "9.1.0",
            "8.6.1",
            "9.0.0",
            "8.6.0",
            "8.5.0",
            "8.4.0",
            "8.3.0",
            "8.2.5",
            "8.2.4",
            "8.2.3",
            "8.2.2",
            "8.2.1",
            "8.2.0",
            "8.1.0",
            "8.0.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-101042.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.270944006Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/101xxx/CVE-2026-101042.json",
        "https://github.com/parse-community/parse-server/security/advisories/GHSA-mr43-w6c2-mvjq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-101042",
        "https://www.vulncheck.com/advisories/parse-server-9.0.0-authentication-bypass-via-unverified-provider-identity"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/101xxx/CVE-2026-101042.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-101042",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500437,
  "published_at": "2026-09-27T16:28:27.452+00:00"
}