{"id":"CVE-2026-44483","aliases":["EUVD-2026-32564","GHSA-c567-44rc-m5hq"],"status":"published","title":"RVF: Prototype pollution in @rvf/set-get reachable via @rvf/core preprocessFormData (HTTP form data)","description":"RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming form data into a nested object) does not block the keys __proto__, constructor, or prototype when walking a path. Because field names in submitted form data are passed directly to setPath via preprocessFormData (and through parseFormData / validate), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on Object.prototype of the running server process. This is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via parseFormData or runs a validator created with createValidator is affected. This vulnerability is fixed in 6.0.4 and 7.0.2.","severity":{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00359,"percentile":0.30116,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1321"],"published":"2026-05-11T16:09:40Z","modified":"2026-10-28T02:30:54Z","fixes":[{"ecosystem":"npm","package":"@rvf/set-get","fixed_in":["7.0.2","6.0.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@rvf/set-get","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.0.2"}]}]},{"source":"ghsa","ecosystem":"npm","package":"@rvf/set-get","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.0.4"}]}]},{"source":"osv","ecosystem":"npm","package":"@rvf/set-get","ranges":[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.0.2"}]}]},{"source":"osv","ecosystem":"npm","package":"@rvf/set-get","ranges":[{"type":"SEMVER","events":[{"introduced":"6.0.0"},{"fixed":"6.0.4"}]}]}],"products":[{"vendor":"@rvf","product":"set-get"},{"vendor":"airjp73","product":"rvf"}],"references":[{"url":"https://github.com/airjp73/rvf/security/advisories/GHSA-c567-44rc-m5hq","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44483","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-c567-44rc-m5hq"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44483.json","tags":["advisory"]},{"url":"https://github.com/airjp73/rvf","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-44483","title":"RVF: Prototype pollution in @rvf/set-get reachable via @rvf/core preprocessFormData (HTTP form data)","description":"RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming form data into a nested object) does not block the keys __proto__, constructor, or prototype when walking a path. Because field names in submitted form data are passed directly to setPath via preprocessFormData (and through parseFormData / validate), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on Object.prototype of the running server process. This is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via parseFormData or runs a validator created with createValidator is affected. This vulnerability is fixed in 6.0.4 and 7.0.2.","status":"published","published":"2026-05-27T15:20:43.045Z","modified":"2026-05-27T18:48:41.768Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high","assessor":"cna"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T13:42:49.132798Z"}],"euvd":[{"id":"EUVD-2026-32564","description":"RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming form data into a nested object) does not block the keys __proto__, constructor, or prototype when walking a path. Because field names in submitted form data are passed directly to setPath via preprocessFormData (and through parseFormData / validate), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on Object.prototype of the running server process. This is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via parseFormData or runs a validator created with createValidator is affected. This vulnerability is fixed in 6.0.4 and 7.0.2.","status":"published","published":"2026-05-27T15:20:43Z","modified":"2026-05-27T18:48:41Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high"}],"updated_at":"2026-11-02T18:21:03.450999Z"}],"ghsa":[{"id":"GHSA-c567-44rc-m5hq","title":"@rvf/set-get has a prototype pollution issue that's reachable via @rvf/core preprocessFormData (HTTP form data)","description":"## Summary\n\n`setPath` in `@rvf/set-get` (used by `@rvf/core` to flatten incoming form data into a nested object) does not block the keys `__proto__`, `constructor`, or `prototype` when walking a path. Because field names in submitted form data are passed directly to `setPath` via `preprocessFormData` (and through `parseFormData` / `validate`), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on `Object.prototype` of the running server process.\n\nThis is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via `parseFormData` or runs a validator created with `createValidator` is affected.\n\n## Affected versions\n\n- `@rvf/set-get` `\u003c 7.0.2` (7.x line)\n- `@rvf/set-get` `\u003c 6.0.4` (6.x line)\n\nReached through `@rvf/core` versions that depend on a vulnerable `@rvf/set-get` (current `8.1.0` resolves to `7.0.1` without the override).\n\n## Patched\n\n- `@rvf/set-get` `7.0.2`\n- `@rvf/set-get` `6.0.4`\n\nThe fix adds a `REJECT_KEYS` blocklist (`__proto__`, `constructor`, `prototype`) and throws when one is encountered while walking a path inside `setPath`.\n\n## Proof of concept\n\nInstall a vulnerable resolution and run on Node 18+:\n\n```json\n{\n  \"dependencies\": { \"@rvf/core\": \"8.1.0\" },\n  \"overrides\": { \"@rvf/set-get\": \"7.0.1\" }\n}\n```\n\n```js\nconst { preprocessFormData } = require('@rvf/core');\n\nconst form = new FormData();\nform.append(\"username\", \"alice\");\nform.append(\"__proto__[polluted]\", \"yes\");\n\npreprocessFormData(form);\nconsole.log(({}).polluted); // -\u003e 'yes'\n```\n\nThe field name `__proto__[polluted]` is the kind of value an attacker can submit from any HTML form or HTTP client. After the call, every plain object in the process inherits `polluted = 'yes'`.\n\nA second working payload is `constructor.prototype.\u003ckey\u003e=\u003cvalue\u003e`, which goes through `setPath` walking `constructor` then `prototype`.\n\n## Impact\n\n- Any property assignable on `Object.prototype` of the server process, set by a single unauthenticated HTTP request.\n- Persists for the life of the worker process and affects every subsequent request handled by the same process.\n- Direct downstream consequences depend on the host application and the rest of its dependency tree, but typical risks include: bypassing `if (obj.isAdmin)` style checks, injecting unintended config values into objects merged with user input, breaking template rendering, and crashing the worker by polluting properties used by other libraries (DoS).\n- Worth noting: the visible output of `preprocessFormData` does not contain the malicious key, so the attack leaves no obvious trace in request logs that show parsed bodies.\n\n## CVSS\n\n`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L` (8.2, High)\n\nIntegrity is High because the primitive lets the attacker change the meaning of property reads on every object in the process. Confidentiality is None and Availability is Low without a named downstream gadget; both could be higher in a specific consuming app.\n\n## Remediation for users\n\nUpgrade to `@rvf/set-get` `7.0.2` or `6.0.4`. If you cannot upgrade `@rvf/core` directly, an `npm` / `pnpm` override on `@rvf/set-get` works.\n\n## Credit\n\nReported by Mohamed Bassia (@0xBassia).","status":"published","published":"2026-05-11T16:09:40Z","modified":"2026-06-08T23:49:05Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:40:21.48274Z"}],"nvd":[{"id":"CVE-2026-44483","description":"RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming form data into a nested object) does not block the keys __proto__, constructor, or prototype when walking a path. Because field names in submitted form data are passed directly to setPath via preprocessFormData (and through parseFormData / validate), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on Object.prototype of the running server process. This is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via parseFormData or runs a validator created with createValidator is affected. This vulnerability is fixed in 6.0.4 and 7.0.2.","status":"published","published":"2026-05-27T17:16:39.51Z","modified":"2026-10-26T11:10:00.157Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high","assessor":"secondary"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:12:20.885865Z"}],"osv":[{"id":"CVE-2026-44483","title":"RVF: Prototype pollution in @rvf/set-get reachable via @rvf/core preprocessFormData (HTTP form data)","description":"RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming form data into a nested object) does not block the keys __proto__, constructor, or prototype when walking a path. Because field names in submitted form data are passed directly to setPath via preprocessFormData (and through parseFormData / validate), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on Object.prototype of the running server process. This is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via parseFormData or runs a validator created with createValidator is affected. This vulnerability is fixed in 6.0.4 and 7.0.2.","status":"published","published":"2026-05-27T15:20:43.045Z","modified":"2026-10-28T02:30:54.225635769Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:45:04.820169Z"},{"id":"GHSA-c567-44rc-m5hq","title":"@rvf/set-get has a prototype pollution issue that's reachable via @rvf/core preprocessFormData (HTTP form data)","description":"## Summary\n\n`setPath` in `@rvf/set-get` (used by `@rvf/core` to flatten incoming form data into a nested object) does not block the keys `__proto__`, `constructor`, or `prototype` when walking a path. Because field names in submitted form data are passed directly to `setPath` via `preprocessFormData` (and through `parseFormData` / `validate`), an attacker who can submit a form to a Remix / React Router app using the library can set arbitrary properties on `Object.prototype` of the running server process.\n\nThis is a default-reachable prototype pollution primitive: no special configuration is required. Any endpoint that accepts a form via `parseFormData` or runs a validator created with `createValidator` is affected.\n\n## Affected versions\n\n- `@rvf/set-get` `\u003c 7.0.2` (7.x line)\n- `@rvf/set-get` `\u003c 6.0.4` (6.x line)\n\nReached through `@rvf/core` versions that depend on a vulnerable `@rvf/set-get` (current `8.1.0` resolves to `7.0.1` without the override).\n\n## Patched\n\n- `@rvf/set-get` `7.0.2`\n- `@rvf/set-get` `6.0.4`\n\nThe fix adds a `REJECT_KEYS` blocklist (`__proto__`, `constructor`, `prototype`) and throws when one is encountered while walking a path inside `setPath`.\n\n## Proof of concept\n\nInstall a vulnerable resolution and run on Node 18+:\n\n```json\n{\n  \"dependencies\": { \"@rvf/core\": \"8.1.0\" },\n  \"overrides\": { \"@rvf/set-get\": \"7.0.1\" }\n}\n```\n\n```js\nconst { preprocessFormData } = require('@rvf/core');\n\nconst form = new FormData();\nform.append(\"username\", \"alice\");\nform.append(\"__proto__[polluted]\", \"yes\");\n\npreprocessFormData(form);\nconsole.log(({}).polluted); // -\u003e 'yes'\n```\n\nThe field name `__proto__[polluted]` is the kind of value an attacker can submit from any HTML form or HTTP client. After the call, every plain object in the process inherits `polluted = 'yes'`.\n\nA second working payload is `constructor.prototype.\u003ckey\u003e=\u003cvalue\u003e`, which goes through `setPath` walking `constructor` then `prototype`.\n\n## Impact\n\n- Any property assignable on `Object.prototype` of the server process, set by a single unauthenticated HTTP request.\n- Persists for the life of the worker process and affects every subsequent request handled by the same process.\n- Direct downstream consequences depend on the host application and the rest of its dependency tree, but typical risks include: bypassing `if (obj.isAdmin)` style checks, injecting unintended config values into objects merged with user input, breaking template rendering, and crashing the worker by polluting properties used by other libraries (DoS).\n- Worth noting: the visible output of `preprocessFormData` does not contain the malicious key, so the attack leaves no obvious trace in request logs that show parsed bodies.\n\n## CVSS\n\n`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L` (8.2, High)\n\nIntegrity is High because the primitive lets the attacker change the meaning of property reads on every object in the process. Confidentiality is None and Availability is Low without a named downstream gadget; both could be higher in a specific consuming app.\n\n## Remediation for users\n\nUpgrade to `@rvf/set-get` `7.0.2` or `6.0.4`. If you cannot upgrade `@rvf/core` directly, an `npm` / `pnpm` override on `@rvf/set-get` works.\n\n## Credit\n\nReported by Mohamed Bassia (@0xBassia).","status":"published","published":"2026-05-11T16:09:40Z","modified":"2026-09-10T03:50:46.500716542Z","cvss":[{"version":"3.1","score":8.2,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:46:44.571161Z"}]}}