Troubleshooting
Problem
After applying the following security PTF clients using the drivers supplied by IBM i Access Client Solutions Windows Application Package versions older than 1.1.0.28 will fail to establish a connection to the IBM i Host Servers.
PTF list:
| IBM I release | Product Number | PTF number |
| 7.4 | 5770SS1 | SJ11103 |
| 7.5 | 5770SS1 | SJ11102 |
| 7.6 | 5770SS1 | SJ11101 |
CVE's covered in the above PTFs:
CVE-2026-17223
CVE-2026-17206
CVE-2026-17208
CVE-2026-16929
CVE-2026-17004
CVE-2026-18846
Symptom
Connection attempts are expected to fail during the initial authentication phase. The specific error presented to the user may vary depending on the client application and driver in use, including:
"CWBSY1000 - Communication error while validating security information on system <system name>"
"CWB0999 - Unexpected error: unexpected return code 8006"
Cause
The cover letters of the above-referenced PTFs include the following text:
The application of this PTF requires the use of clients that are
current as of August 2026. Failures may occur with
out-of-support clients.Resolving The Problem
The IBM i Signon Host Server enforces hardened security requirements and an updated IBM i ACS Windows Application Package. The minimum version of the IBM i Access Client Solutions Windows Application Package that is required is version 1.1.0.28.
In the Windows environment, find the currently installed version of the Access Client Solutions Windows Application Package by executing "cwbprops.exe", or by opening the Windows ODBC driver and checking the IBM i Access ODBC driver version on the "Drivers" tab. The driver version "13.64.28.00" corresponds with ACS Application Package version 1.1.0.28.
Related Information
Document Location
Worldwide
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Document Information
Modified date:
10 September 2026
UID
ibm17284076