Security Bulletin
Summary
Multiple security vulnerabilities have been identified in netty-codec-smtp, Netty/Codec/SMTP. netty-codec-smtp is used by IBM Infosphere Change Data Capture. IBM has addressed these vulnerabilities. Refer to the "Remediation/Fixes" section below for remediation details.
Vulnerability Details
CVEID: CVE-2026-93563
DESCRIPTION: A flaw was found in Netty's `SmtpResponseDecoder` component. A remote attacker, acting as a malicious or man-in-the-middle (MITM) SMTP server, could exploit this by sending a specially crafted, unbounded multi-line SMTP response without a terminator. This vulnerability leads to unbounded memory accumulation within the client's Java Virtual Machine (JVM) heap, causing an `OutOfMemoryError` and a denial of service (DoS) due to a process crash.
CWE: CWE-1035: OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CVSS Source: secalert@redhat.com
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2026-93576
DESCRIPTION: 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.
CWE: CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')
CVSS Source: secalert@redhat.com
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| InfoSphere Data Replication | 11.4 |
| InfoSphere Data Replication | 11.4.0 |
Remediation/Fixes
Fix is available in IDR 11.4.0.5-5826. Please refer to fix central link http://www.ibm.com/support/fixcentral/swg/quickorder?parent=ibm%3FInformation%20Management&product=ibm/Information+Management/IBM+InfoSphere+Data+Replication&release=11.4&platform=All&function=all&source=fc
Workarounds and Mitigations
netty-codec-smtp has been upgraded to netty-codec-smtp-4.1.139.Final non-vulnerable version.
The fix will be available in an upcoming product release.
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
26 Oct 2026: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
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Document Information
Modified date:
26 October 2026
Initial Publish date:
26 October 2026
UID
ibm17294021