Vulnerability in react-router (CVE-2026-42342)
Summary
Vulnerability in react-router (CVE-2026-42342). Risk of unauthorized operations or information disclosure. Exploitable via createBrowserRouter. Mitigation: upgrade to 7.15.0 or later.
Original description
The description as published by the source.
There exists a potential DOS attack vector in React Router Framework Mode applications (as well as Remix v2.10.0 - 2.17.4). Certain requests can be crafted to consume disproportionate resources on the server, resulting in response time degredation and/or service unavailability for end users.
[!NOTE]
This does not impact your React Router application if you are using Declarative Mode () or [Data Mode](https://reactrouter.com/start/modes#data) (`createBrowserRouter`/).
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42342 has been found in react-router.
Attackers can target a specific entry point like createBrowserRouter over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade react-router to 7.15.0 or later.
If unsure, ask your IT team or search "react-router CVE-2026-42342" on the vendor's site.
CVE-2026-42342 (react-router) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: createBrowserRouter
Patched: 7.15.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in react-router. Attackers reach the vulnerable code path via createBrowserRouter without authentication.
Check the vendor advisory for the affected versions of react-router. Attack surface: createBrowserRouter.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 7.15.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'react-router' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'react-router' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
react-routerを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade react-router to 7.15.0ステージング環境で 7.15.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- patch security-advisories@github.com
- web github.com