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CVE-2026-14631 medium CVSS 5.3

Vulnerability in webpack-dev-server (CVE-2026-14631)

Summary

vulnerability in webpack-dev-server (CVE-2026-14631). Risk of unauthorized operations or information disclosure. Exploitable via ``Host``. Mitigation: upgrade to `5.2.6` or later.

AI summary snake-internal / snake-material-v2

A vulnerability tracked as **CVE-2026-14631** has been found in webpack-dev-server. Attackers can target a specific entry point like ``Host`` over the network to misuse the product. Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10. What to do: upgrade webpack-dev-server to **5.2.6** or later. If unsure, ask your IT team or search "webpack-dev-server CVE-2026-14631" on the vendor's site.
CVE-2026-14631 (webpack-dev-server) — CWE-20 / CVSS v3 5.3 Attack vector: remote (network-reachable) / unauthenticated / no user interaction Attack surface: `Host` / `Origin` / `localhost` Patched: `5.2.6` — apply immediately Workaround: Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks. 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.
❓ What is the problem
**A vulnerability** (CWE-20) exists in webpack-dev-server. Attackers reach the vulnerable code path via ``Host`` without authentication.
📍 Affected scope
webpack-dev-server — . Attack surface: `Host` / `Origin` / `localhost`.
🔥 Severity
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **5.2.6**.
🛡️ Workaround
Workaround: Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'webpack-dev-server' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response Actions (7 steps)

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify
    grep -r 'webpack-dev-server' . | 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 `webpack-dev-server` を grep し、稼働しているサービス・バージョンを把握する。

  2. 5
    Apply temporary workaround mitigate
    Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks.

    パッチが適用されるまでの応急処置として、Keep the dev server bound to `localhost` (the default) and do not expose it to untrusted networks. を実施。回避策の副作用 (機能低下) を確認した上で。

  3. 6
    Apply patch patch
    Upgrade webpack-dev-server to 5.2.6

    ステージング環境で 5.2.6 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と、Step 3 で見つけた異常検知の続報チェックを含めること。

  4. 7
    Post-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 Step 3 と同じログクエリでアラート再発が無いか継続監視。

Affected packages

npm webpack-dev-server
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.2.6"}]}]

References

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