IBM MQ Appliance is affected by vulnerabilities in IBM WebSphere Application Server Liberty

IBM MQ Appliance has addressed multiple vulnerabilities in IBM WebSphere Application Server Liberty.

Vulnerability Details

CVEID: CVE-2026-11541 DESCRIPTION: IBM CICS Transaction Gateway for Multiplatforms 9.1, 9.2, 9.3, and 10.1 IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are affected by an HTTP request smuggling vulnerability. CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CVSS Source: IBM CVSS Base score: 7.4 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) CVEID: CVE-2026-9071 DESCRIPTION: IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are vulnerable to a denial of service, caused by sending a specially-crafted request. A remote attacker could exploit this vulnerability to cause the server to consume memory resources. CWE: CWE-400: Uncontrolled Resource Consumption CVSS Source: IBM 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-2026-9320 DESCRIPTION: IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are vulnerable to a denial of service, caused by sending a specially-crafted request. A remote attacker could exploit this vulnerability to cause the server to consume memory resources. CWE: CWE-400: Uncontrolled Resource Consumption CVSS Source: IBM CVSS Base score: 5.9 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H) CVEID: CVE-2026-8646 DESCRIPTION: IBM WebSphere Application Server 9.0 and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are vulnerable to HTTP request smuggling. A remote attacker could smuggle a specially crafted request to the application server thereby allowing the attacker to bypass security controls, spoof identity, escalate privilege, and expose sensitive information. CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CVSS Source: IBM CVSS Base score: 7.4 CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N) CVEID: CVE-2026-50645 DESCRIPTION: There is no restriction on the amount of attachment headers that a message can contain when being deserialized by Apache CXF, which can lead to uncontrolled resource consumption or a denial of service attack. Users are recommended to upgrade to versions 4.2.2 or 4.1.7 or 3.6.12, which fix this issue by imposing a maximum default of 500 attachments per message. CWE: CWE-400: Uncontrolled Resource Consumption CVSS Source: NVD 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-2026-9322 DESCRIPTION: IBM WebSphere Application Server 9.0, and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.7 are vulnerable to a denial of service via a crafted HTTP request. CWE: CWE-400: Uncontrolled Resource Consumption CVSS Source: IBM 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-2026-9171 DESCRIPTION: IBM WebSphere Application Server and WebSphere Application Server Liberty are vulnerable to a denial of service, caused by sending a specially-crafted request. A remote attacker could exploit this vulnerability to cause the server to consume memory resources. CWE: CWE-400: Uncontrolled Resource Consumption CVSS Source: IBM 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)

Affected Products and Versions

Affected Product(s) Version(s) IBM MQ Appliance 9.4 LTS - 9.4.0.0 to 9.4.0.25 IBM MQ Appliance 9.4 CD - 9.4.1.0 to 9.4.5.2 IBM MQ Appliance 10.0.0.0 - 10.0.0.1 only

This vulnerability is addressed under APAR DT475062. IBM strongly recommends addressing the vulnerability now. IBM MQ Appliance version 9.4 LTS Apply IBM MQ Appliance cumulative security update 9.4.0.26, or later firmware. IBM MQ Appliance version 9.4 CD - M2003 Upgrade to IBM MQ Appliance 10.0.0.5, or later firmware. IBM MQ Appliance version 9.4 CD - M2002 Apply IBM MQ Appliance cumulative security update 9.4.5.3, or later firmware. IBM MQ Appliance version 10 LTS Apply IBM MQ Appliance fix pack 10.0.0.5, or later firmware.

This vulnerability is addressed under APAR DT475062.

IBM strongly recommends addressing the vulnerability now.

IBM MQ Appliance version 9.4 LTS Apply IBM MQ Appliance cumulative security update 9.4.0.26, or later firmware.

IBM MQ Appliance version 9.4 CD - M2003 Upgrade to IBM MQ Appliance 10.0.0.5, or later firmware.

IBM MQ Appliance version 9.4 CD - M2002 Apply IBM MQ Appliance cumulative security update 9.4.5.3, or later firmware.

IBM MQ Appliance version 10 LTS Apply IBM MQ Appliance fix pack 10.0.0.5, or later firmware.

Workarounds and Mitigations

Get Notified Future Security Bulletins

Complete CVSS v3 Guide On-line Calculator v3

10 Sep 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.

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.

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.

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Modified date: 10 September 2026

Initial Publish date: 10 September 2026