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CVE-2026-40606
Vulnerability in mitmproxy (CVE-2026-40606)
Summary
vulnerability in mitmproxy (CVE-2026-40606). Risk of unauthorized operations or information disclosure. Exploitable via ``proxyauth``. Mitigation: upgrade to `12.2.2` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-40606** has been found in mitmproxy.
Attackers can target a specific entry point like ``proxyauth`` over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: ?/10.
What to do: upgrade mitmproxy to **12.2.2** or later.
If unsure, ask your IT team or search "mitmproxy CVE-2026-40606" on the vendor's site.
CVE-2026-40606 (mitmproxy) — CWE-90 /
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: `proxyauth`
Patched: `12.2.2` — 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.
❓ What is the problem
**A vulnerability** (CWE-90) exists in mitmproxy. Attackers reach the vulnerable code path via ``proxyauth`` without authentication.
📍 Affected scope
mitmproxy — . Attack surface: `proxyauth`.
🔥 Severity
Severity: ?. Risk of unauthorized operations or information disclosure
🔧 How to fix
Update to **12.2.2**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run `grep -r 'mitmproxy' .` 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 'mitmproxy' . | 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 `mitmproxy` 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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6Apply patch patch
Upgrade mitmproxy to 12.2.2ステージング環境で 12.2.2 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。
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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
PyPI
mitmproxy
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"12.2.2"}]}]
pip
mitmproxy
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"12.2.2"}]}]
References
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-40606
- package https://github.com/mitmproxy/mitmproxy
- web https://github.com/mitmproxy/mitmproxy/security/advisories/GHSA-527g-3w9m-29hv
- web https://github.com/pypa/advisory-database/tree/main/vulns/mitmproxy/PYSEC-2026-92.yaml
- web https://github.com/advisories/GHSA-527g-3w9m-29hv