CVE-2026-1918: IBM Sterling Information Disclosure Flaw

CVE-2026-1918 Overview

CVE-2026-1918 is an information disclosure vulnerability affecting IBM Sterling B2B Integrator and IBM Sterling File Gateway. The affected products write potentially sensitive information into log files that can be read by a privileged local user. The weakness is classified under [CWE-532] (Insertion of Sensitive Information into Log File).

Exploitation requires high privileges and does not affect integrity or availability, but the confidentiality impact is high. Sensitive data recovered from log files can support lateral movement, credential reuse, or further compromise of connected trading-partner systems.

Critical Impact
A privileged user with access to log files can retrieve sensitive information written by IBM Sterling B2B Integrator or Sterling File Gateway, enabling downstream credential misuse or exposure of transferred data.

Affected Products

IBM Sterling B2B Integrator 6.2.0.0 through 6.2.0.5_2, 6.2.1.0 through 6.2.1.1_2, and 6.2.2.0 through 6.2.2.0_1
IBM Sterling File Gateway 6.2.0.0 through 6.2.0.5_2, 6.2.1.0 through 6.2.1.1_2, and 6.2.2.0 through 6.2.2.0_1
Deployments sharing log storage with additional privileged operators or backup systems

Discovery Timeline

2026-07-28 - CVE-2026-1918 published to the National Vulnerability Database
2026-07-29 - Last updated in the NVD database

Technical Details for CVE-2026-1918

Vulnerability Analysis

IBM Sterling B2B Integrator and Sterling File Gateway handle business-to-business file transfers, EDI processing, and partner integration workflows. During normal operation, the platform emits diagnostic and audit records to log files on the application server.

The vulnerability stems from the products recording potentially sensitive information into those log files. Any operator, administrator, or backup process with privileged read access to the log directory can inspect the data. The attack vector is network-facing according to the CVSS metrics, reflecting that the logging behavior is triggered by remote transactions, though the disclosure surface itself is the local log store.

Because Sterling B2B Integrator brokers partner credentials, payload metadata, and transfer control data, exposed log entries can include material that is more privileged than the log reader's normal authorization. This creates a privilege-boundary violation even when the reader is authorized to view logs generally.

Root Cause

The root cause is improper filtering of sensitive fields before they are serialized into log output. Under [CWE-532], data such as session identifiers, credentials, or payload metadata is written verbatim rather than masked, redacted, or omitted. IBM has published product guidance under the referenced support note.

Attack Vector

A privileged user with read access to the log files reviews stored logs and extracts sensitive values written by Sterling B2B Integrator or Sterling File Gateway. No authentication bypass or memory-corruption primitive is required; the attacker uses legitimate access to a lower-sensitivity resource (logs) to obtain higher-sensitivity data. No public proof-of-concept or exploit code is available for this issue.

Detection Methods for CVE-2026-1918

Indicators of Compromise

Unexpected read access to Sterling B2B Integrator or Sterling File Gateway log directories by accounts outside the platform administration group
Copying, archiving, or exfiltration of log files to endpoints or shares not part of the approved backup path
Grep or search activity against log files targeting keywords such as password, token, authorization, or partner identifiers

Detection Strategies

Audit filesystem access to Sterling log paths and alert on reads by non-service accounts
Deploy data loss prevention rules that match sensitive patterns emitted to log files, including credentials or trading-partner secrets
Correlate privileged shell sessions on Sterling hosts with subsequent access to log archives

Monitoring Recommendations

Forward Sterling B2B Integrator and File Gateway logs to a central SIEM with strict access controls and immutable retention
Baseline normal log-access patterns and alert on deviations by user, time, or volume
Review privileged account entitlements on Sterling hosts on a recurring cadence to enforce least privilege

How to Mitigate CVE-2026-1918

Immediate Actions Required

Apply the fixed release referenced in the IBM Support Page for Sterling B2B Integrator and Sterling File Gateway
Restrict filesystem permissions on log directories to the minimum set of service and administrator accounts
Rotate any credentials, tokens, or keys that may have been captured in existing log files

Patch Information

IBM has issued remediation guidance for the affected Sterling B2B Integrator and Sterling File Gateway versions 6.2.0.0 through 6.2.0.5_2, 6.2.1.0 through 6.2.1.1_2, and 6.2.2.0 through 6.2.2.0_1. Refer to the IBM Support Page for the current fix pack and upgrade instructions.

Workarounds

Reduce log verbosity to the lowest level compatible with operational requirements until patches are applied
Sanitize or purge historical log files that may contain sensitive fields exposed by the vulnerability
Segment log storage from general-purpose administrator access and require just-in-time elevation for log review

bash

# Example: tighten access to Sterling B2B Integrator log directories on Linux
chown -R sterling:sterling /opt/IBM/SI/logs
chmod -R 750 /opt/IBM/SI/logs
find /opt/IBM/SI/logs -type f -exec chmod 640 {} \;