Netty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery
Summary
Netty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery
Original description
The description as published by the source.
Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.128.Final and 4.2.7.Final, the SMTP codec in Netty contains an SMTP command injection vulnerability due to insufficient input validation for Carriage Return (\r) and Line Feed (\n) characters in user-supplied parameters. The vulnerability exists in io.netty.handler.codec.smtp.DefaultSmtpRequest, where parameters are directly concatenated into the SMTP command string without sanitization. When methods such as SmtpRequests.rcpt(recipient) are called with a malicious string containing CRLF sequences, attackers can inject arbitrary SMTP commands. Because the injected commands are sent from the server's trusted IP address, resulting emails will likely pass SPF and DKIM authentication checks, making them appear legitimate. This allows remote attackers who can control SMTP command parameters (such as email recipients) to forge arbitrary emails from the trusted server, potentially impersonating executives and forging high-stakes corporate communications. This issue has been patched in versions 4.1.129.Final and 4.2.8.Final. No known workarounds exist.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2025-59419 netty Fixed in: 1:4.1.48-4+deb11u3
- Ubuntu UBUNTU-CVE-2025-59419 netty Fixed in: 1:4.1.7-4ubuntu0.1+esm4
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- patch github.com
- web depthfirst.com