CVE-2026-16689: IBM App Connect Enterprise Information Disclosure

CVE-2026-16689 Overview

CVE-2026-16689 is an information disclosure vulnerability in IBM App Connect Enterprise and IBM Integration Bus for z/OS. The flaw stems from improper logging of credentials, allowing a local attacker with low privileges to read sensitive authentication data from log files. The issue is classified under [CWE-532] (Insertion of Sensitive Information into Log File).

Critical Impact
A local authenticated attacker can retrieve credentials from log files, enabling lateral movement and unauthorized access to integration endpoints and connected systems.

Affected Products

IBM App Connect Enterprise 13.0.1.0 through 13.0.8.1
IBM App Connect Enterprise 12.0.1.0 through 12.0.12.28
IBM Integration Bus for z/OS 10.1.0.0 through 10.1.0.7

Discovery Timeline

2026-09-04 - CVE-2026-16689 published to NVD
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-16689

Vulnerability Analysis

The vulnerability resides in the credential handling logic of IBM App Connect Enterprise and IBM Integration Bus for z/OS. Affected components write sensitive credential material into log files during normal operation. Any local user with read access to those log files can extract the credentials.

The attack requires local access and low privileges, but no user interaction. Exploitation impacts confidentiality only; integrity and availability of the integration server remain intact. Credentials recovered from logs may include those used by message flows to authenticate to databases, queue managers, or downstream services.

Root Cause

The root cause is improper sanitization of log output. Code paths that handle authentication and configuration data emit credential fields to log streams without masking or redaction. This is a classic [CWE-532] weakness where sensitive information persists on disk beyond the memory lifecycle of the request.

Attack Vector

An attacker with a local shell on the host running App Connect Enterprise or Integration Bus reads the diagnostic or trace logs generated by the broker runtime. Because the logs contain plaintext credentials, the attacker can reuse them to authenticate against services that trust the integration server. The vulnerability requires no exploit code; standard file read operations on the log directory are sufficient.

See the IBM Support Article for vendor-specific technical details on the affected log paths and credential types.

Detection Methods for CVE-2026-16689

Indicators of Compromise

Unexpected read access to App Connect Enterprise or Integration Bus log directories by non-service accounts.
Presence of credential-like strings (passwords, API keys, connection strings) in userlog, trace, or diagnostic files.
Authentication events from integration service accounts originating from unexpected hosts or processes.

Detection Strategies

Scan broker log directories for patterns matching password fields, JDBC connection strings, and MQ authentication tokens.
Correlate file access telemetry on log paths with process identity to identify non-runtime processes reading trace output.
Alert on downstream service authentication failures immediately following log access events by unusual users.

Monitoring Recommendations

Enable file integrity and access monitoring on /var/mqsi/, broker workpath, and z/OS equivalent log destinations.
Forward broker log access events to a centralized SIEM for correlation with account activity.
Review scheduled jobs, backup agents, and third-party tools that ingest broker logs to confirm they do not export credentials off-host.

How to Mitigate CVE-2026-16689

Immediate Actions Required

Apply the IBM-provided fix pack for App Connect Enterprise 12 and 13, and Integration Bus for z/OS 10.1 as documented in the IBM Support Article.
Rotate any credentials that may have been written to log files on affected systems.
Restrict filesystem permissions on broker log directories to the runtime service account only.

Patch Information

IBM has published remediation guidance in the IBM Support Article covering IBM App Connect Enterprise versions 12.0.1.0 through 12.0.12.28 and 13.0.1.0 through 13.0.8.1, and IBM Integration Bus for z/OS 10.1.0.0 through 10.1.0.7. Upgrade to the fixed release specified in the advisory.

Workarounds

Reduce broker trace and log verbosity to levels that do not capture credential material until patches are applied.
Purge or archive existing log files that may contain exposed credentials, then restrict access to the archive.
Move log storage to a directory protected by strict access control lists, and audit membership of any group with read access.

bash

# Configuration example
# Restrict broker log directory access to the runtime service account
chown -R mqbrkrs:mqbrkrs /var/mqsi/components/<broker>/log
chmod -R 700 /var/mqsi/components/<broker>/log

# Lower trace verbosity on a running integration node
mqsichangetrace <IntegrationNodeName> -t none -l none