CVE-2026-125755 (CVSS 6.5)

Description

Nodemailer 3.0.0 before 10.4.1 contains an address parsing flaw in addressparser that truncates domains at folding whitespace or comments before a dot, allowing attackers to bypass recipient domain restrictions. Attackers can submit crafted to, cc, bcc or replyTo addresses that pass RFC 5322 domain checks but deliver mail to an attacker-chosen address under the application's sender identity.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-436 CWE-436

References

Other References

https://github.com/nodemailer/nodemailer/blob/3b5cf1eec32c81f287870c8a1c9c09640062cfd5/src/addressparser/index.ts#L330-L345 https://github.com/nodemailer/nodemailer/commit/c2b9c41bb81b2294ebadd294ad15ff035a17d0a5 https://github.com/nodemailer/nodemailer/releases/tag/v10.4.1 https://github.com/nodemailer/nodemailer/security/advisories/GHSA-3q53-mvfw-q9v8 https://www.vulncheck.com/advisories/nodemailer-3.0.0-before-10.4.1-recipient-allow-list-bypass-via-addressparser

Frequently Asked Questions

What is CVE-2026-125755? +

Nodemailer 3.0.0 before 10.4.1 contains an address parsing flaw in addressparser that truncates domains at folding whitespace or comments before a dot, allowing attackers to bypass recipient domain restrictions. Attackers can submit crafted to, cc, bcc or replyTo addresses that pass RFC 5322 domain checks but deliver mail to an attacker-chosen address under the application's sender identity. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-125755? +

CVE-2026-125755 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-125755? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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