OAuth2 credential interception via disabled TLS verification
Published Aug 31, 2026 · Updated Aug 31, 2026
Improper TLS certificate validation in Nodemailer before 8.0.8 allows man-in-the-middle attackers to capture OAuth2 credentials. The internal HTTPS client in lib/fetch/index.js sets rejectUnauthorized to false, so OAuth2 token requests accept self-signed, invalid-chain, and hostname-mismatched certificates. Exploitation requires control of the OAuth2 HTTPS path and exposes client secrets, refresh tokens, and access tokens while permitting token-response tampering.
Summary
What happened
Improper TLS certificate validation in Nodemailer before 8.0.8 allows man-in-the-middle attackers to capture OAuth2 credentials. The internal HTTPS client in lib/fetch/index.js sets rejectUnauthorized to false, so OAuth2 token requests accept self-signed, invalid-chain, and hostname-mismatched certificates. Exploitation requires control of the OAuth2 HTTPS path and exposes client secrets, refresh tokens, and access tokens while permitting token-response tampering.
The record
- CVE
- CVE-2026-82662
- Published
- Aug 31, 2026
- Updated
- Aug 31, 2026
- Vendor
- Nodemailer
- Product
- Nodemailer
- Classifications
- CWE-295, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 31, 2026CVE publishedPublication date reported by the CVE source.
- Aug 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <8.0.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Self-signed OAuth endpoint proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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