BlackTreeCVE Intelligencenetty · netty
Official source article: GitHub GHSA-JQ43-27X9-3V86 ↗. Check the applicable product and release in the original source.
Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | netty | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:4.1.48-10+deb13u1 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian bookwormbookworm · source | netty | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:4.1.48-7+deb12u2 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian forkyforky · source | netty | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:4.1.48-11 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Debian sidsid · source | netty | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:4.1.48-11 | Debian Security Tracker ↗Source updated 5 Oct 2026 |
| Ubuntu 24.04 LTSnoble · esm-apps | netty | Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree. | 1:4.1.48-9ubuntu0.1~esm2 | Canonical Ubuntu Security ↗Source updated 5 Oct 2026 |
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| Mavenio.netty:netty-codec-smtp | ECOSYSTEM: introduced 4.2.0.Alpha1; fixed 4.2.7.Final | 4.2.7.Final | OSV record ↗aggregator derived · 10 Sep 2026 |
| Mavenio.netty:netty-codec-smtp | ECOSYSTEM: introduced 0; fixed 4.1.128.Final | 4.1.128.Final | OSV record ↗aggregator derived · 10 Sep 2026 |
| mavenio.netty:netty-codec-smtp | >= 4.2.0.Alpha1, < 4.2.7.Final | 4.2.7.Final | GitHub advisory ↗upstream repository advisory · 17 Oct 2025 |
| mavenio.netty:netty-codec-smtp | < 4.1.128.Final | 4.1.128.Final | GitHub advisory ↗upstream repository advisory · 17 Oct 2025 |
Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Fix not verifiedNetty 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.
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.
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
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.
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection'). The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:PCommon Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
Operational remediation based on structured source evidence.
Published 15 Oct 2025 · Last source change 17 Oct 2025, 19:44 UTC · CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')
Core structured fields are present and their contributing authorities are shown above.
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.