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CVE-2026-9675
high
CVSS 7.5
Vulnerability in undici (CVE-2026-9675)
Summary
vulnerability in undici (CVE-2026-9675). Risk of unauthorized operations or information disclosure. Exploitable via ``maxPayloadSize``. Mitigation: upgrade to `8.5.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-9675** has been found in undici.
Attackers can target a specific entry point like ``maxPayloadSize`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade undici to **8.5.0** or later.
If unsure, ask your IT team or search "undici CVE-2026-9675" on the vendor's site.
CVE-2026-9675 (undici) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `maxPayloadSize`
Patched: `8.5.0` — apply immediately
Workaround: No workaround is available.
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-400) exists in undici. Attackers reach the vulnerable code path via ``maxPayloadSize`` without authentication.
📍 Affected scope
undici — . Attack surface: `maxPayloadSize`.
🔥 Severity
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **8.5.0**.
🛡️ Workaround
Workaround: No workaround is available.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'undici' .` 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
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1Identify exposure identify
grep -r 'undici' . | 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 `undici` を grep し、稼働しているサービス・バージョンを把握する。
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5Apply temporary workaround mitigate
No workaround is available.パッチが適用されるまでの応急処置として、No workaround is available. を実施。回避策の副作用 (機能低下) を確認した上で。
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6Apply patch patch
Upgrade undici to 8.5.0ステージング環境で 8.5.0 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。
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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
undici
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.5.0"}]}]