Security Bulletin
Summary
The python package h11 is used by IBM Fusion and IBM Fusion HCI as part of the Content Aware Storage service and the Backup and Restore service agent and is vulnerable to request smuggling under certain conditions due to CVE-2025-43859 in h11.
Vulnerability Details
CVEID: CVE-2025-43859
DESCRIPTION: h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.
CWE: CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVSS Source: security-advisories@github.com
CVSS Base score: 9.1
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM Fusion | 2.9.1 |
| IBM Fusion IBM Fusion HCI IBM Fusion HCI for watsonx | 2.9.0 |
| IBM Fusion IBM Fusion HCI IBM Fusion HCI for watsonx | 2.8.2 |
| IBM Fusion | 2.8.0 |
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now.
| Product(s) | Version(s) number and/or range | Remediation/Fix/Instructions |
| IBM Fusion | 2.8.0 - 2.9.1 | Upgrade to 2.10.0 - See README for upgrade instructions. |
| IBM Fusion HCI | 2.8.2 - 2.9.0 | Upgrade to 2.10.0 - See README for upgrade instructions. |
| IBM Fusion HCI for watsonx | 2.8.2 - 2.9.0 | Upgrade to 2.10.0 - See README for upgrade instructions. |
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
17 Jun 2025: 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:
17 June 2025
Initial Publish date:
17 June 2025
UID
ibm17237050