Sign in Sign up
JA · EN · FR
SecPulse
Categories
CVE-2026-40701 medium CVSS 4.8

Use-After-Free in nginx (CVE-2026-40701)

Summary

Vulnerability in nginx (CVE-2026-40701). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.30.1 or later.

Original description

The description as published by the source.

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssl_module module when the ssl_verify_client directive is set to "on" or "optional," and the ssl_ocsp directive is set to "on" or the leaf parameters are configured with a resolver. With this configuration, an unauthenticated attacker can send requests along with conditions beyond its control that may cause a heap-use-after-free error in the NGINX worker process. This vulnerability may result in limited modification of data or the NGINX worker process restarting.

 Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Source: NIST National Vulnerability Database 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-2026-40701 has been found in nginx.
Risk of unauthorized operations or information disclosure. CVSS score: 4.8/10.
What to do: upgrade nginx to 1.30.1 or later.
If unsure, ask your IT team or search "nginx CVE-2026-40701" on the vendor's site.

CVE-2026-40701 (nginx) — CWE-416 / CVSS v3 4.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 1.30.1 — 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

Use-after-free (CWE-416) exists in nginx.

📍 Affected scope

Check the vendor advisory for the affected versions of nginx.

🔥 Severity

Severity: Medium (CVSS 4.8/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.30.1.

🛡️ 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 'nginx' . 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 'nginx' . | 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 nginx 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 nginx to 1.30.1

    ステージング環境で 1.30.1 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

Bitnami nginx
[{"type":"SEMVER","events":[{"introduced":"1.19.0"},{"fixed":"1.30.1"}]}]
Bitnami nginx-gateway
[{"type":"SEMVER","events":[{"introduced":"1.19.0"},{"fixed":"1.30.1"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

We use cookies for analytics and ad measurement. This setting applies to all Game co., Ltd. sites. Details