← Back
CVE-2026-6270
critical
CVSS 9.1
Vulnerability in @fastify/middie (CVE-2026-6270)
Summary
vulnerability in @fastify/middie (CVE-2026-6270). Confidential information can be exposed externally. Mitigation: upgrade to `9.3.2` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-6270** has been found in @fastify/middie.
Confidential information can be exposed externally. CVSS score: 9.1/10.
What to do: upgrade @fastify/middie to **9.3.2** or later.
If unsure, ask your IT team or search "@fastify/middie CVE-2026-6270" on the vendor's site.
CVE-2026-6270 (@fastify/middie) — CWE-436 / CVSS v3 9.1
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: `9.3.2` — apply immediately
Workaround: None.
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-436) exists in @fastify/middie.
📍 Affected scope
@fastify/middie — .
🔥 Severity
Severity: Critical (CVSS 9.1/10). Confidential information can be exposed externally
🔧 How to fix
Update to **9.3.2**.
🛡️ Workaround
Workaround: None.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r '@fastify/middie' .` 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
-
1Identify exposure identify
grep -r '@fastify/middie' . | 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 `@fastify/middie` を grep し、稼働しているサービス・バージョンを把握する。
-
5Apply temporary workaround mitigate
None.パッチが適用されるまでの応急処置として、None. を実施。回避策の副作用 (機能低下) を確認した上で。
-
6Apply patch patch
Upgrade @fastify/middie to 9.3.2ステージング環境で 9.3.2 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。
-
7Post-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
@fastify/middie
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"9.3.2"}]}]
References
- web https://cna.openjsf.org/security-advisories.html
- web https://github.com/fastify/fastify-express/security/advisories/GHSA-hrwm-hgmj-7p9c
- web https://github.com/fastify/middie/security/advisories/GHSA-72c6-fx6q-fr5w
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-6270
- package https://github.com/fastify/middie