---
id: CVE-2026-93576
title: A flaw was found in Netty netty-codec-smtp
summary: >-
  A flaw was found in Netty netty-codec-smtp. The component does not properly
  validate Carriage Return (CR) and Line Feed (LF) characters in the SMTP
  command-name field. A remote attacker, if an application routes untrusted
  input into this…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-93
vendor: Red Hat
product: netty-codec-smtp
affected:
  - netty-codec-smtp (all versions)
  - netty-codec-smtp (all versions)
  - jboss-eap-7/eap74-els-openjdk11-openshift-rhel8 (all versions)
  - jboss-eap-7/eap74-els-openjdk17-openshift-rhel8 (all versions)
  - jboss-eap-7/eap74-els-openjdk8-openshift-rhel8 (all versions)
  - netty-codec-smtp (all versions)
  - netty-codec-smtp (all versions)
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T21:18:48.540'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93576'
references:
  - url: 'https://access.redhat.com/security/cve/CVE-2026-93576'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536968'
    label: secalert@redhat.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93576.json
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-93576'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-93576'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-18T14:58:44.082356Z'
ingestedAt: '2026-09-18T14:43:13.060Z'
epss: 0.00269
epssPercentile: 0.19384
---

## Overview

A flaw was found in Netty netty-codec-smtp. The component does not properly validate Carriage Return (CR) and Line Feed (LF) characters in the SMTP command-name field. A remote attacker, if an application routes untrusted input into this field, can embed CR/LF characters to inject arbitrary SMTP commands. This can lead to SMTP command smuggling, allowing for unauthorized email relay or spoofing of sender/recipient addresses. While the impact is significant, the real-world exploitability is considered lower as applications typically do not place user-controlled data in the command-name field.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · no fix planned: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93576.json)