Security Bulletin
Summary
Open source packages are used as part of the overall processing in DataStage on Cloud Pak for Data
Vulnerability Details
CVEID: CVE-2026-9675
DESCRIPTION: Impact:
The undici WebSocket client enforces maxPayloadSize per-frame but does not enforce the cumulative size of fragmented uncompressed messages. A malicious WebSocket server can stream many small fragments that each pass per-frame validation but collectively exceed the configured limit, causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service.
Affected applications are those using the undici WebSocket client (new WebSocket(...)) that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.
This is a regression specific to undici 8.1.0. The 6.25.0 line shipped the equivalent cumulative check from the start and is unaffected. The 7.x line never had the maxPayloadSize feature and is also unaffected.
Patches:
Upgrade to undici = 8.5.0.
Workarounds:
No workaround is available. The fix must be applied through an upgrade.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: openjs
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) |
| DataStage on Cloud Pak for Data | 5.4.0.0 |
| DataStage on Cloud Pak for Data | 5.3.1.0 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now by upgrading DataStage on Cloud Pak for Data.
| Product(s) | Version(s) number and/or range | Remediation/Fix/Instructions |
| DataStage on Cloud Pak for Data | 5.3.1.0 |
Upgrade to 5.3.1 patch 11 or later by following these instructions. Upgrade to 5.4.0.0 patch 5 or later by following these instructions. |
| DataStage on Cloud Pak for Data | 5.4.0.0 |
Upgrade to 5.4.0.0 patch 5 or later by following these instructions. |
Workarounds and Mitigations
None
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References
Acknowledgement
Change History
04 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:
04 September 2026
Initial Publish date:
04 September 2026
UID
ibm17286435