Email forgery via unvalidated SMTP parameters
Published Oct 15, 2025 · Updated Oct 15, 2025
SMTP command injection in Netty before 4.1.128.Final and 4.2.7.Final allows remote attackers to forge email via controlled SMTP parameters. DefaultSmtpRequest concatenates parameter values into encoded SMTP commands without rejecting carriage returns or line feeds, allowing one value to introduce additional commands. Exploitation requires a consuming application to pass attacker-controlled sender, recipient, or hostname data to the SMTP codec; resulting mail originates from the trusted server and can impersonate another sender.
Summary
What happened
SMTP command injection in Netty before 4.1.128.Final and 4.2.7.Final allows remote attackers to forge email via controlled SMTP parameters. DefaultSmtpRequest concatenates parameter values into encoded SMTP commands without rejecting carriage returns or line feeds, allowing one value to introduce additional commands. Exploitation requires a consuming application to pass attacker-controlled sender, recipient, or hostname data to the SMTP codec; resulting mail originates from the trusted server and can impersonate another sender.
The record
- CVE
- CVE-2025-59419
- Published
- Oct 15, 2025
- Updated
- Oct 15, 2025
- Vendor
- The Netty Project
- Product
- Netty
- Classifications
- CWE-93, T1036
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 15, 2025CVE publishedPublication date reported by the CVE source.
- Oct 15, 2025Record 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=>= 4.2.0.Alpha1, < 4.1.128.Final
- Affected versionversion=< 4.2.7.Final
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.
Weakness, pattern, technique
Public exploit references
- poc-netty-smtp-injection.javaproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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