Vulnerability-Lookup

GHSA-XHQ9-58FW-859P

Vulnerability from github – Published: 2026-04-16 20:42 – Updated: 2026-04-16 20:42

Summary

ApostropheCMS: publicApiProjection Bypass via project Query Builder in Piece-Type REST API

Details

Summary

The getRestQuery method in the @apostrophecms/piece-type module checks whether a MongoDB projection has already been set before applying the admin-configured publicApiProjection. An unauthenticated attacker can supply a project query parameter in the REST API request to pre-populate the projection state, causing the security-enforced publicApiProjection to be skipped entirely. This allows disclosure of fields that the site administrator explicitly restricted from public access.

Details

When an unauthenticated user queries the piece-type REST API, the getRestQuery method processes the request at modules/@apostrophecms/piece-type/index.js:1120:

// piece-type/index.js:1120-1137
getRestQuery(req, omitPermissionCheck = false) {
  const query = self.find(req).attachments(true);
  query.applyBuildersSafely(req.query);          // [1] attacker input applied first
  if (!omitPermissionCheck && !self.canAccessApi(req)) {
    if (!self.options.publicApiProjection) {
      query.and({
        _id: null
      });
    } else if (!query.state.project) {            // [2] checks if projection already set
      query.project({
        ...self.options.publicApiProjection,
        cacheInvalidatedAt: 1
      });
    }
  }
  return query;
},

At [1], applyBuildersSafely iterates over all query string parameters and invokes their corresponding builder methods. The project builder exists in @apostrophecms/doc-type with a launder method (doc-type/index.js:1876) that sanitizes values to booleans:

// doc-type/index.js:1875-1889
project: {
  launder (p) {
    if (!p || typeof p !== 'object' || Array.isArray(p)) {
      return {};
    }
    const projection = Object.entries(p).reduce((acc, [ key, val ]) => {
      return {
        ...acc,
        [key]: self.apos.launder.boolean(val)
      };
    }, {});
    return projection;
  },

When a request includes ?project[someField]=1, the builder sets query.state.project to {someField: true}. At [2], the conditional !query.state.project evaluates to false because the state is already populated, so the publicApiProjection is never applied.

For comparison, the @apostrophecms/page module's equivalent method (page/index.js:2953) unconditionally applies the projection:

// page/index.js:2953-2958
} else {
  query.project({
    ...self.options.publicApiProjection,
    cacheInvalidatedAt: 1
  });
}

PoC

Prerequisites: An ApostropheCMS 4.x instance with a piece-type (e.g., article) that has publicApiProjection configured to restrict fields. For example:

// modules/article/index.js
module.exports = {
  extend: '@apostrophecms/piece-type',
  options: {
    publicApiProjection: {
      title: 1,
      _url: 1
    }
  }
};

Step 1: Normal request — observe restricted fields are hidden:

curl 'http://localhost:3000/api/v1/article'

Response returns only title and _url fields per the configured projection.

Step 2: Bypass projection by supplying project query parameter:

curl 'http://localhost:3000/api/v1/article?project[internalNotes]=1&project[title]=1&project[slug]=1&project[createdAt]=1'

Response now includes internalNotes, slug, createdAt, and any other requested fields — bypassing the admin-configured publicApiProjection restriction.

Step 3: Request all default fields by projecting inclusion of sensitive fields:

curl 'http://localhost:3000/api/v1/article?project[_id]=1&project[title]=1&project[slug]=1&project[visibility]=1&project[type]=1&project[createdAt]=1&project[updatedAt]=1'

All requested fields are returned, confirming the publicApiProjection is fully bypassed.

Impact

Information Disclosure: An unauthenticated attacker can read any field on documents that are already publicly queryable, bypassing administrator-configured field restrictions. This may expose internal notes, draft content, metadata, or other sensitive fields the administrator intentionally hid from the public API.
Scope: Affects all piece-type modules with publicApiProjection configured. The attacker cannot access documents they wouldn't otherwise be able to query (document-level permissions still apply), but they can read any field on accessible documents.
Exploitability: Trivial — requires only appending query parameters to a public URL. No authentication, special tools, or chaining required.

Recommended Fix

Remove the conditional check on query.state.project in piece-type/index.js, matching the page module's unconditional behavior. The admin-configured publicApiProjection should always override any user-supplied projection for unauthenticated users:

// modules/@apostrophecms/piece-type/index.js:1123-1134
// BEFORE (vulnerable):
if (!omitPermissionCheck && !self.canAccessApi(req)) {
  if (!self.options.publicApiProjection) {
    query.and({
      _id: null
    });
  } else if (!query.state.project) {
    query.project({
      ...self.options.publicApiProjection,
      cacheInvalidatedAt: 1
    });
  }
}

// AFTER (fixed):
if (!omitPermissionCheck && !self.canAccessApi(req)) {
  if (!self.options.publicApiProjection) {
    query.and({
      _id: null
    });
  } else {
    query.project({
      ...self.options.publicApiProjection,
      cacheInvalidatedAt: 1
    });
  }
}

Severity

5.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "apostrophe"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.29.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33888"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T20:42:21Z",
    "nvd_published_at": "2026-04-15T20:16:35Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nThe `getRestQuery` method in the `@apostrophecms/piece-type` module checks whether a MongoDB projection has already been set before applying the admin-configured `publicApiProjection`. An unauthenticated attacker can supply a `project` query parameter in the REST API request to pre-populate the projection state, causing the security-enforced `publicApiProjection` to be skipped entirely. This allows disclosure of fields that the site administrator explicitly restricted from public access.\n\n## Details\n\nWhen an unauthenticated user queries the piece-type REST API, the `getRestQuery` method processes the request at `modules/@apostrophecms/piece-type/index.js:1120`:\n\n```javascript\n// piece-type/index.js:1120-1137\ngetRestQuery(req, omitPermissionCheck = false) {\n  const query = self.find(req).attachments(true);\n  query.applyBuildersSafely(req.query);          // [1] attacker input applied first\n  if (!omitPermissionCheck \u0026\u0026 !self.canAccessApi(req)) {\n    if (!self.options.publicApiProjection) {\n      query.and({\n        _id: null\n      });\n    } else if (!query.state.project) {            // [2] checks if projection already set\n      query.project({\n        ...self.options.publicApiProjection,\n        cacheInvalidatedAt: 1\n      });\n    }\n  }\n  return query;\n},\n```\n\nAt **[1]**, `applyBuildersSafely` iterates over all query string parameters and invokes their corresponding builder methods. The `project` builder exists in `@apostrophecms/doc-type` with a `launder` method (`doc-type/index.js:1876`) that sanitizes values to booleans:\n\n```javascript\n// doc-type/index.js:1875-1889\nproject: {\n  launder (p) {\n    if (!p || typeof p !== \u0027object\u0027 || Array.isArray(p)) {\n      return {};\n    }\n    const projection = Object.entries(p).reduce((acc, [ key, val ]) =\u003e {\n      return {\n        ...acc,\n        [key]: self.apos.launder.boolean(val)\n      };\n    }, {});\n    return projection;\n  },\n```\n\nWhen a request includes `?project[someField]=1`, the builder sets `query.state.project` to `{someField: true}`. At **[2]**, the conditional `!query.state.project` evaluates to `false` because the state is already populated, so the `publicApiProjection` is never applied.\n\nFor comparison, the `@apostrophecms/page` module\u0027s equivalent method (`page/index.js:2953`) unconditionally applies the projection:\n\n```javascript\n// page/index.js:2953-2958\n} else {\n  query.project({\n    ...self.options.publicApiProjection,\n    cacheInvalidatedAt: 1\n  });\n}\n```\n\n## PoC\n\n**Prerequisites:** An ApostropheCMS 4.x instance with a piece-type (e.g., `article`) that has `publicApiProjection` configured to restrict fields. For example:\n\n```javascript\n// modules/article/index.js\nmodule.exports = {\n  extend: \u0027@apostrophecms/piece-type\u0027,\n  options: {\n    publicApiProjection: {\n      title: 1,\n      _url: 1\n    }\n  }\n};\n```\n\n**Step 1:** Normal request \u2014 observe restricted fields are hidden:\n\n```bash\ncurl \u0027http://localhost:3000/api/v1/article\u0027\n```\n\nResponse returns only `title` and `_url` fields per the configured projection.\n\n**Step 2:** Bypass projection by supplying `project` query parameter:\n\n```bash\ncurl \u0027http://localhost:3000/api/v1/article?project[internalNotes]=1\u0026project[title]=1\u0026project[slug]=1\u0026project[createdAt]=1\u0027\n```\n\nResponse now includes `internalNotes`, `slug`, `createdAt`, and any other requested fields \u2014 bypassing the admin-configured `publicApiProjection` restriction.\n\n**Step 3:** Request all default fields by projecting inclusion of sensitive fields:\n\n```bash\ncurl \u0027http://localhost:3000/api/v1/article?project[_id]=1\u0026project[title]=1\u0026project[slug]=1\u0026project[visibility]=1\u0026project[type]=1\u0026project[createdAt]=1\u0026project[updatedAt]=1\u0027\n```\n\nAll requested fields are returned, confirming the `publicApiProjection` is fully bypassed.\n\n## Impact\n\n- **Information Disclosure:** An unauthenticated attacker can read any field on documents that are already publicly queryable, bypassing administrator-configured field restrictions. This may expose internal notes, draft content, metadata, or other sensitive fields the administrator intentionally hid from the public API.\n- **Scope:** Affects all piece-type modules with `publicApiProjection` configured. The attacker cannot access documents they wouldn\u0027t otherwise be able to query (document-level permissions still apply), but they can read any field on accessible documents.\n- **Exploitability:** Trivial \u2014 requires only appending query parameters to a public URL. No authentication, special tools, or chaining required.\n\n## Recommended Fix\n\nRemove the conditional check on `query.state.project` in `piece-type/index.js`, matching the page module\u0027s unconditional behavior. The admin-configured `publicApiProjection` should always override any user-supplied projection for unauthenticated users:\n\n```javascript\n// modules/@apostrophecms/piece-type/index.js:1123-1134\n// BEFORE (vulnerable):\nif (!omitPermissionCheck \u0026\u0026 !self.canAccessApi(req)) {\n  if (!self.options.publicApiProjection) {\n    query.and({\n      _id: null\n    });\n  } else if (!query.state.project) {\n    query.project({\n      ...self.options.publicApiProjection,\n      cacheInvalidatedAt: 1\n    });\n  }\n}\n\n// AFTER (fixed):\nif (!omitPermissionCheck \u0026\u0026 !self.canAccessApi(req)) {\n  if (!self.options.publicApiProjection) {\n    query.and({\n      _id: null\n    });\n  } else {\n    query.project({\n      ...self.options.publicApiProjection,\n      cacheInvalidatedAt: 1\n    });\n  }\n}\n```",
  "id": "GHSA-xhq9-58fw-859p",
  "modified": "2026-04-16T20:42:21Z",
  "published": "2026-04-16T20:42:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-xhq9-58fw-859p"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33888"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/commit/00d472804bb622df36a761b6f2cf2b33b2d4ce80"
    },
    {
      "type": "WEB",
      "url": "https://github.com/apostrophecms/apostrophe/commit/6c2b548dec2e3f7a82e8e16736603f4cd17525aa"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/apostrophecms/apostrophe"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ApostropheCMS: publicApiProjection Bypass via project Query Builder in Piece-Type REST API"
}

CVE-2026-33888 (GCVE-0-2026-33888)

Vulnerability from cvelistv5 – Published: 2026-04-15 19:25 – Updated: 2026-04-15 20:03

Title

ApostropheCMS: publicApiProjection Bypass via `project` Query Builder in Piece-Type REST API

Summary

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain an authorization bypass vulnerability in the getRestQuery method of the @apostrophecms/piece-type module, where the method checks whether a MongoDB projection has already been set before applying the admin-configured publicApiProjection. An unauthenticated attacker can supply a project query parameter in the REST API request, which is processed by applyBuildersSafely before the permission check, pre-populating the projection state and causing the publicApiProjection to be skipped entirely. This allows disclosure of any field on publicly queryable documents that the administrator explicitly restricted from the public API, such as internal notes, draft content, or metadata. Exploitation is trivial, requiring only appending query parameters to a public URL with no authentication. This issue has been fixed in version 4.29.0.

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-04-15 20:03 UTC

CWE

CWE-863 - Incorrect Authorization
CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor

Assigner

GitHub_M mitre root Scorecard

References

3 references

URL	Tags
https://github.com/apostrophecms/apostrophe/secur…	x_refsource_CONFIRM
https://github.com/apostrophecms/apostrophe/commi…	x_refsource_MISC
https://github.com/apostrophecms/apostrophe/commi…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
apostrophecms	apostrophe	Affected: < 4.29.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33888",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-15T20:03:13.844941Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-15T20:03:30.594Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "apostrophe",
          "vendor": "apostrophecms",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.29.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain an authorization bypass vulnerability in the getRestQuery method of the @apostrophecms/piece-type module, where the method checks whether a MongoDB projection has already been set before applying the admin-configured publicApiProjection. An unauthenticated attacker can supply a project query parameter in the REST API request, which is processed by applyBuildersSafely before the permission check, pre-populating the projection state and causing the publicApiProjection to be skipped entirely. This allows disclosure of any field on publicly queryable documents that the administrator explicitly restricted from the public API, such as internal notes, draft content, or metadata. Exploitation is trivial, requiring only appending query parameters to a public URL with no authentication. This issue has been fixed in version 4.29.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-863",
              "description": "CWE-863: Incorrect Authorization",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-200",
              "description": "CWE-200: Exposure of Sensitive Information to an Unauthorized Actor",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-15T19:25:46.262Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-xhq9-58fw-859p",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-xhq9-58fw-859p"
        },
        {
          "name": "https://github.com/apostrophecms/apostrophe/commit/00d472804bb622df36a761b6f2cf2b33b2d4ce80",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/apostrophecms/apostrophe/commit/00d472804bb622df36a761b6f2cf2b33b2d4ce80"
        },
        {
          "name": "https://github.com/apostrophecms/apostrophe/commit/6c2b548dec2e3f7a82e8e16736603f4cd17525aa",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/apostrophecms/apostrophe/commit/6c2b548dec2e3f7a82e8e16736603f4cd17525aa"
        }
      ],
      "source": {
        "advisory": "GHSA-xhq9-58fw-859p",
        "discovery": "UNKNOWN"
      },
      "title": "ApostropheCMS: publicApiProjection Bypass via `project` Query Builder in Piece-Type REST API"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33888",
    "datePublished": "2026-04-15T19:25:46.262Z",
    "dateReserved": "2026-03-24T15:10:05.681Z",
    "dateUpdated": "2026-04-15T20:03:30.594Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-XHQ9-58FW-859P

Summary

Details

PoC

Impact

Recommended Fix

CVE-2026-33888 (GCVE-0-2026-33888)

Tags

Sightings

Nomenclature

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