Security Bulletin
Summary
IBM WebSphere Application Server Liberty prior to 26.0.0.9 is affected by multiple vulnerabilities.
Vulnerability Details
CVEID: CVE-2026-10841
DESCRIPTION: IBM WebSphere Application Server 8.5, 9.0, and Liberty are vulnerable to HTTP request smuggling.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: IBM
CVSS Base score: 4.2
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-11548
DESCRIPTION: IBM WebSphere Application Server and WebSphere Application Server Liberty 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: 4.8
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-11549
DESCRIPTION: IBM WebSphere Application Server and WebSphere Application Server Liberty are affected by a virtual host bypass vulnerability.
CWE: CWE-284: Improper Access Control
CVSS Source: IBM
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-11722
DESCRIPTION: IBM WebSphere Application Server and WebSphere Application Server Liberty 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: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-15396
DESCRIPTION: IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: IBM
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-15412
DESCRIPTION: IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty could allow a remote attacker to conduct phishing attacks, using an open redirect attack. By persuading a victim to visit a specially crafted Web site, a remote attacker could exploit this vulnerability to spoof the URL displayed to redirect a user to a malicious Web site that would appear to be trusted. This could allow the attacker to obtain highly sensitive information or conduct further attacks against the victim.
CWE: CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
CVSS Source: IBM
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
CVEID: CVE-2026-15634
DESCRIPTION: IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: IBM
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| WebSphere Application Server - Liberty | 17.0.0.3 - 26.0.0.8 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerabilities now by applying the fix pack listed below.
For IBM WebSphere Application Server Liberty 17.0.0.3 - 26.0.0.8:
· Apply Liberty Fix Pack 26.0.0.9 (availability September 2026) or later fix pack.
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
08 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.
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:
08 September 2026
Initial Publish date:
08 September 2026
UID
ibm17286611