Vulnerability in Nodemailer (CVE-2026-100701)
Summary
Vulnerability in Nodemailer (CVE-2026-100701). Confidential information can be exposed externally. Mitigation: upgrade to 10.0.2 or later.
Original description
The description as published by the source.
Nodemailer versions 5.0.0 through 10.0.1 use a process-global DNS cache that is keyed only by the DNS host, while each cache entry also stores the caller-specific TLS servername. When two direct TLS/SMTPS transports (secure: true) resolve the same non-IP host with different tls.servername values, the first transport's servername is returned on the cache hit and overwrites the second transport's explicitly configured value, so Nodemailer sends the wrong SNI value and validates the peer certificate against the wrong identity. In multi-tenant services or SNI-routed SMTP gateways, an attacker who can prime the cache can cause a victim transport to connect to the attacker's TLS virtual host and accept the attacker's certificate even with rejectUnauthorized: true, disclosing the victim's SMTP credentials. Fixed in 10.0.2.
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-2026-100701 has been found in Nodemailer.
Confidential information can be exposed externally. CVSS score: 5.9/10.
What to do: upgrade Nodemailer to 10.0.2 or later.
If unsure, ask your IT team or search "Nodemailer CVE-2026-100701" on the vendor's site.
CVE-2026-100701 (Nodemailer) — CWE-295 / CVSS v3 5.9
Attack vector: remote (network-reachable) / no user interaction
Patched: 10.0.2 — 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.
A vulnerability (CWE-295) exists in Nodemailer.
Check the vendor advisory for the affected versions of Nodemailer.
Severity: Medium (CVSS 5.9/10). Confidential information can be exposed externally.
Update to 10.0.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Nodemailer' . 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
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1Identify exposure identify
grep -r 'Nodemailer' . | 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
Nodemailerを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Nodemailer to 10.0.2ステージング環境で 10.0.2 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を含めること。
-
3Post-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。
References
- web github.com
- web vulncheck.com
- web nvd.nist.gov
- web github.com