CVE-2026-42211: CWE-502: Deserialization of Untrusted Data in remix-run react-router
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.
AI Analysis
Technical Summary
CVE-2026-42211 affects remix-run react-router in versions >=7.0.0 and <7.14.2 when operating in Framework Mode. The vulnerability involves deserialization of untrusted data that, combined with an existing prototype pollution vulnerability in the application code, can be exploited in a two-step attack to achieve unauthorized remote code execution on the server. Declarative Mode (<BrowserRouter>) and Data Mode (createBrowserRouter/<RouterProvider>) are not impacted. The vulnerability has a CVSS 3.1 score of 8.1, indicating high severity. The issue is resolved in version 7.14.2.
Potential Impact
Successful exploitation can result in remote code execution on the server, leading to full compromise of the affected system. The attack requires the presence of a prototype pollution vulnerability in the application code, making it a chained attack scenario. Confidentiality, integrity, and availability of the affected system are all highly impacted.
Mitigation Recommendations
Upgrade react-router to version 7.14.2 or later, where this vulnerability is patched. Applications using Declarative Mode or Data Mode are not affected by this issue. No other specific mitigations are indicated. Patch status is confirmed by the vendor advisory stating the fix is in 7.14.2.
CVE-2026-42211: CWE-502: Deserialization of Untrusted Data in remix-run react-router
Description
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.
CVSS v3.1
Score 8.1high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42211 affects remix-run react-router in versions >=7.0.0 and <7.14.2 when operating in Framework Mode. The vulnerability involves deserialization of untrusted data that, combined with an existing prototype pollution vulnerability in the application code, can be exploited in a two-step attack to achieve unauthorized remote code execution on the server. Declarative Mode (<BrowserRouter>) and Data Mode (createBrowserRouter/<RouterProvider>) are not impacted. The vulnerability has a CVSS 3.1 score of 8.1, indicating high severity. The issue is resolved in version 7.14.2.
Potential Impact
Successful exploitation can result in remote code execution on the server, leading to full compromise of the affected system. The attack requires the presence of a prototype pollution vulnerability in the application code, making it a chained attack scenario. Confidentiality, integrity, and availability of the affected system are all highly impacted.
Mitigation Recommendations
Upgrade react-router to version 7.14.2 or later, where this vulnerability is patched. Applications using Declarative Mode or Data Mode are not affected by this issue. No other specific mitigations are indicated. Patch status is confirmed by the vendor advisory stating the fix is in 7.14.2.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-25T05:04:37.028Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f3494e29bf47b50fa2521
Added to database: 06/02/2026, 19:52:52 UTC
Last enriched: 06/10/2026, 11:09:48 UTC
Last updated: 07/31/2026, 19:24:49 UTC
Views: 54
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.