Vulnerability in react-router (CVE-2026-55685)
Summary
Vulnerability in react-router (CVE-2026-55685). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 7.18.0 or later.
Original description
The description as published by the source.
This is a follow up to https://github.com/remix-run/react-router/security/advisories/GHSA-8x6r-g9mw-2r78 that covers additional reported scenarios in which the manifest endpoint could be accessed via unauthenticated targeted requests that would put heavy load on the server and slow down response times.
[!NOTE]
This only impacts Framework Mode applications. This does not impact your application if you are using Declarative or Data Mode.
Source: GitHub Security Advisories (Global) 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-2026-55685 has been found in react-router.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade react-router to 7.18.0 or later.
If unsure, ask your IT team or search "react-router CVE-2026-55685" on the vendor's site.
CVE-2026-55685 (react-router) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 7.18.0 — 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.
Check the vendor advisory for the affected versions of react-router.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 7.18.0.
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
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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 7.18.0ステージング環境で 7.18.0 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 security-advisories@github.com
- advisory security-advisories@github.com
- patch security-advisories@github.com
- patch security-advisories@github.com
- web security-advisories@github.com
- web security-advisories@github.com
- web github.com