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CVE-2026-44431 medium CVSS 5.3

Information Disclosure in urllib3 (CVE-2026-44431)

Summary

Vulnerability in urllib3 (CVE-2026-44431). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 2.7.0 or later.

Original description

The description as published by the source.

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

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-2026-44431 has been found in urllib3.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade urllib3 to 2.7.0 or later.
If unsure, ask your IT team or search "urllib3 CVE-2026-44431" on the vendor's site.

CVE-2026-44431 (urllib3) — CWE-200 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 2.7.0 — 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.

❓ What is the problem

Information disclosure (CWE-200) exists in urllib3.

📍 Affected scope

Check the vendor advisory for the affected versions of urllib3.

🔥 Severity

Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 2.7.0.

🛡️ 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 'urllib3' . 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

  1. 1
    Identify exposure identify 
    grep -r 'urllib3' . | 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 urllib3 を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade urllib3 to 2.7.0

    ステージング環境で 2.7.0 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。

  3. 3
    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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

pip urllib3
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.7.0"}]}]
PyPI urllib3
[{"type":"ECOSYSTEM","events":[{"introduced":"1.23"},{"fixed":"2.7.0"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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