CVE-2026-40181: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in remix-run react-router
React Router is a router for React. In versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3, certain URLs passed to the redirect function can trigger an open redirect to an external domain due to path values starting with // being reinterpreted as protocol-relative URLs. The level of impact depends on the validation done by the application prior to returning the redirect. This does not impact applications using Declarative Mode (<BrowserRouter>). This is patched in versions 7.14.1 and 6.30.4.
AI Analysis
Technical Summary
CVE-2026-40181 is an open redirect vulnerability in the remix-run react-router library affecting versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3. The issue arises because the redirect function mishandles URLs starting with //, treating them as protocol-relative URLs and allowing redirection to external domains. The impact depends on the application's validation of redirect URLs. Applications using Declarative Mode (<BrowserRouter>) are not vulnerable. The vulnerability has a CVSS 4.0 score of 6.6 (medium severity) and is fixed in versions 7.14.1 and 6.30.4.
Potential Impact
The vulnerability allows an attacker to craft URLs that cause the application to redirect users to untrusted external sites, potentially facilitating phishing or other malicious activities. The actual impact depends on how the application validates redirect URLs before invoking the redirect function. There is no indication of known exploits in the wild.
Mitigation Recommendations
Upgrade react-router to version 7.14.1 or later, or 6.30.4 or later, where this open redirect vulnerability is patched. Applications using Declarative Mode (<BrowserRouter>) are not affected by this issue. No other mitigation is indicated.
CVE-2026-40181: CWE-601: URL Redirection to Untrusted Site ('Open Redirect') in remix-run react-router
Description
React Router is a router for React. In versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3, certain URLs passed to the redirect function can trigger an open redirect to an external domain due to path values starting with // being reinterpreted as protocol-relative URLs. The level of impact depends on the validation done by the application prior to returning the redirect. This does not impact applications using Declarative Mode (<BrowserRouter>). This is patched in versions 7.14.1 and 6.30.4.
CVSS v4.0
Score 6.6medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-40181 is an open redirect vulnerability in the remix-run react-router library affecting versions 7.0.0 through 7.14.0 and 6.7.0 through 6.30.3. The issue arises because the redirect function mishandles URLs starting with //, treating them as protocol-relative URLs and allowing redirection to external domains. The impact depends on the application's validation of redirect URLs. Applications using Declarative Mode (<BrowserRouter>) are not vulnerable. The vulnerability has a CVSS 4.0 score of 6.6 (medium severity) and is fixed in versions 7.14.1 and 6.30.4.
Potential Impact
The vulnerability allows an attacker to craft URLs that cause the application to redirect users to untrusted external sites, potentially facilitating phishing or other malicious activities. The actual impact depends on how the application validates redirect URLs before invoking the redirect function. There is no indication of known exploits in the wild.
Mitigation Recommendations
Upgrade react-router to version 7.14.1 or later, or 6.30.4 or later, where this open redirect vulnerability is patched. Applications using Declarative Mode (<BrowserRouter>) are not affected by this issue. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-09T20:59:17.619Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f348ce29bf47b50fa1ff9
Added to database: 06/02/2026, 19:52:44 UTC
Last enriched: 06/10/2026, 11:05:40 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 125
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