Security Bulletin
Summary
IBM i is vulnerable to denial of service [CVE-2026-11897, CVE-2026-15057, CVE-2026-14981, CVE-2026-64958, CVE-2026-57819, CVE-2026-54225], HTTP response smuggling [CVE-2026-15064, CVE-2026-15328, CVE-2026-15325], and bypassing of security constraints [CVE-2026-10842] in WebSphere Application Server Liberty as described in the vulnerability details section.
Vulnerability Details
CVEID: CVE-2026-11897
DESCRIPTION: IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.7 is 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-770: Allocation of Resources Without Limits or Throttling
CVSS Source: IBM
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
CVEID: CVE-2026-15057
DESCRIPTION: IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.7 is vulnerable to a denial of service due to uncontrolled heap allocation.
CWE: CWE-787: Out-of-bounds Write
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-2026-14981
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 affected by a denial of service vulnerability in the HTTP channel due to unbounded allocation of resources without limits.
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-2026-15064
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 is vulnerable to HTTP Response Smuggling due to improper handling of non-standard HTTP version tokens.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: IBM
CVSS Base score: 8.7
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N)
CVEID: CVE-2026-15328
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 is vulnerable to HTTP request smuggling.
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-2026-15325
DESCRIPTION: IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty is vulnerable to HTTP request smuggling due to improper handling of TRACE requests.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: IBM
CVSS Base score: 8.7
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N)
CVEID: CVE-2026-57819
DESCRIPTION: Apache CXF allows to set a limit on the number of form parameters in a JAX-RS message via the "maxFormParameterCount" configuration option. However, no default limit is set which may lead to denial of service attacks when processing requests with very large numbers of form parameters. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue by using a default limit of 500 parameters.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: CISA ADP
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-2026-54225
DESCRIPTION: Apache CXF allows to control the maximum attachment size via the "attachment-max-size". Prior to Apache CXF 4.2.3 and 4.1.8 and 3.6.12, there was no default placed on this size, meaning that a denial of service attack is possible if the user doesn't explicitly set the limit. Users should update to Apache CXF 4.2.3 or 4.1.8 or 3.6.12 which fixes this problem by imposing a default attachment size limit of 50mb.
CWE: CWE-770: Allocation of Resources Without Limits or Throttling
CVSS Source: CISA ADP
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-2026-64958
DESCRIPTION: An incomplete fix for CVE-2026-50645 means that it is still possible to perform a denial of service attack on Apache CXF by sending a message with many attachment headers. Users are recommended to upgrade to versions 4.2.3 or 4.1.8 or 3.6.12, which fix this issue.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: CISA ADP
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-2026-10842
DESCRIPTION: IBM WebSphere Application Server 8.5, and 9.0 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.7 Traditional and Liberty could allow a remote attacker to bypass security constraints.
CWE: CWE-289: Authentication Bypass by Alternate Name
CVSS Source: IBM
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM i | 7.6 |
| IBM i | 7.5 |
| IBM i | 7.4 |
| IBM i | 7.3 |
Remediation/Fixes
| IBM i Release | 5770-SS1 Option 3 PTF Number(s) | PTF Download Link(s) |
| 7.6 | SJ11027 | https://www.ibm.com/mysupport/s/fix-information?legacy=SJ11027 |
| 7.5 | SJ11028 | https://www.ibm.com/mysupport/s/fix-information?legacy=SJ11028 |
| 7.4 | SJ11029 | https://www.ibm.com/mysupport/s/fix-information?legacy=SJ11029 |
| 7.3 | SJ11030 | https://www.ibm.com/mysupport/s/fix-information?legacy=SJ11030 |
IBM recommends users running unsupported versions of affected products upgrade to a supported and fixed version of affected products.
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
21 Aug 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:
21 August 2026
Initial Publish date:
21 August 2026
UID
ibm17284593