Vulnerability-Lookup

GHSA-49RJ-9FVP-4H2H

Vulnerability from github – Published: 2026-06-03 21:03 – Updated: 2026-06-03 21:03

Summary

React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE

Details

When using React Router v7 in Framework Mode, there exists a combination of steps that could potentially allow unauthorized RCE through external requests. This first requires the application code to have an existing prototype pollution vulnerability. This can be leveraged into a 2-step attack in which the second step can trigger unauthorized RCE on the remote server.

[!NOTE] This does not impact your React Router application if you are using Declarative Mode (<BrowserRouter>) or Data Mode (createBrowserRouter/<RouterProvider>).

Severity

8.1 (High)


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

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 7.14.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "react-router"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.14.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42211"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-502"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-03T21:03:32Z",
    "nvd_published_at": "2026-06-02T20:16:36Z",
    "severity": "HIGH"
  },
  "details": "When using React Router v7 in [Framework Mode](https://reactrouter.com/start/modes#framework), there exists a combination of steps that could potentially allow unauthorized RCE through external requests.  This first requires the application code to have an existing prototype pollution vulnerability.  This can be leveraged into a 2-step attack in which the second step can trigger unauthorized RCE on the remote server.\n\n\u003e [!NOTE]\n\u003e This does not impact your React Router application if you are using [Declarative Mode](https://reactrouter.com/start/modes#declarative) (`\u003cBrowserRouter\u003e`) or [Data Mode](https://reactrouter.com/start/modes#data) (`createBrowserRouter`/`\u003cRouterProvider\u003e`).",
  "id": "GHSA-49rj-9fvp-4h2h",
  "modified": "2026-06-03T21:03:32Z",
  "published": "2026-06-03T21:03:32Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42211"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/remix-run/react-router"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "React Router\u0027s vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE"
}

CVE-2026-42211 (GCVE-0-2026-42211)

Vulnerability from cvelistv5 – Published: 2026-06-02 18:18 – Updated: 2026-06-03 14:08

Title

React Router's vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE

Summary

React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`<BrowserRouter>`) or Data Mode (`createBrowserRouter/<RouterProvider>`). This is patched in version 7.14.2.

Severity

8.1 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-03 14:01 UTC

CWE

CWE-502 - Deserialization of Untrusted Data

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/remix-run/react-router/securit…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
remix-run	react-router	Affected: >= 7.0.0, < 7.14.2

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-42211",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-03T14:01:21.166754Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-03T14:08:30.154Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "react-router",
          "vendor": "remix-run",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 7.0.0, \u003c 7.14.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "React Router is a router for React. In versions 7.0.0 through 7.14.1, when using Framework Mode, a combination of steps could potentially allow unauthorized remote code execution (RCE) through external requests. This attack requires the application code to have an existing prototype pollution vulnerability, which can then be leveraged in a 2-step attack where the second step triggers unauthorized RCE on the remote server. This does not impact applications using Declarative Mode (`\u003cBrowserRouter\u003e`) or Data Mode (`createBrowserRouter/\u003cRouterProvider\u003e`). This is patched in version 7.14.2."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-502",
              "description": "CWE-502: Deserialization of Untrusted Data",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-02T18:18:46.706Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/remix-run/react-router/security/advisories/GHSA-49rj-9fvp-4h2h"
        }
      ],
      "source": {
        "advisory": "GHSA-49rj-9fvp-4h2h",
        "discovery": "UNKNOWN"
      },
      "title": "React Router\u0027s vendored turbo-stream v2 allows arbitrary constructor invocation via TYPE_ERROR deserialization leading to Unauth RCE"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-42211",
    "datePublished": "2026-06-02T18:18:46.706Z",
    "dateReserved": "2026-04-25T05:04:37.028Z",
    "dateUpdated": "2026-06-03T14:08:30.154Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.
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GHSA-49RJ-9FVP-4H2H

CVE-2026-42211 (GCVE-0-2026-42211)

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