Security Bulletin
Summary
IBM WebSphere Liberty Operator is affected by multiple vulnerabilities.
Vulnerability Details
CVEID: CVE-2026-33814
DESCRIPTION: When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0.
CWE: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
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-2026-25680
DESCRIPTION: Parsing arbitrary HTML can consume excessive CPU time, possibly leading to denial of service.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: CISA ADP
CVSS Base score: 6.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)
CVEID: CVE-2026-25681
DESCRIPTION: Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
CWE: CWE-1021: Improper Restriction of Rendered UI Layers or Frames
CVSS Source: CISA ADP
CVSS Base score: 6.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
CVEID: CVE-2026-27136
DESCRIPTION: Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
CWE: CWE-1021: Improper Restriction of Rendered UI Layers or Frames
CVSS Source: CISA ADP
CVSS Base score: 6.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
CVEID: CVE-2026-39821
DESCRIPTION: The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".
CWE: CWE-1289: Improper Validation of Unsafe Equivalence in Input
CVSS Source: CISA ADP
CVSS Base score: 9.6
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N)
CVEID: CVE-2026-42502
DESCRIPTION: Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
CWE: CWE-1021: Improper Restriction of Rendered UI Layers or Frames
CVSS Source: CISA ADP
CVSS Base score: 6.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
CVEID: CVE-2026-42506
DESCRIPTION: Parsing arbitrary HTML which is then rendered using Render can result in an unexpected HTML tree. This can be leveraged to execute XSS attacks in applications that attempt to sanitize input HTML before rendering.
CWE: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS Source: CISA ADP
CVSS Base score: 6.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| WebSphere Liberty Operator | 1.0.0 - 1.6.1 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now by upgrading to WebSphere Liberty Operator v1.6.2, following these instructions.
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
24 Jun 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:
24 June 2026
Initial Publish date:
24 June 2026
UID
ibm17277767