CVE-2026-6544: IBM Concert Information Disclosure Flaw

CVE-2026-6544 Overview

CVE-2026-6544 affects IBM Concert versions 1.0.0 through 3.0.0. The vulnerability allows recursive copying of directories without proper controls. This behavior can lead to unintentional inclusion of sensitive or unnecessary files during copy operations. The resulting exposure increases the attack surface available to a local actor.

The weakness is classified under [CWE-552] (Files or Directories Accessible to External Parties). IBM published an advisory in the IBM Support Document describing the issue and the fixed release.

Critical Impact
A local attacker with access to the system can gain confidentiality impact by reading sensitive files unintentionally included in recursive directory copy operations.

Affected Products

IBM Concert 1.0.0 through 3.0.0
Deployments on Linux kernel-based hosts
Environments where IBM Concert performs recursive copy operations across trust boundaries

Discovery Timeline

2026-09-24 - CVE-2026-6544 published to the National Vulnerability Database
2026-09-28 - Last updated in NVD database

Technical Details for CVE-2026-6544

Vulnerability Analysis

IBM Concert performs recursive directory copy operations without enforcing controls over which files are included. The copy routine traverses directory trees and duplicates every file it encounters. This behavior does not distinguish between application artifacts and sensitive files that may reside in the same path.

The vulnerability requires local access and does not require authentication or user interaction. An attacker who can influence source or destination directories can cause sensitive files to be exposed to a less-trusted location. Impact is limited to confidentiality; the issue does not affect integrity or availability.

Root Cause

The root cause maps to [CWE-552], where files or directories become accessible to parties that should not have access. The recursive copy function lacks allowlists, denylists, permission checks, or filtering based on file sensitivity. As a result, credentials, configuration files, keys, or logs stored in traversed paths can be propagated to destinations with weaker access controls.

Attack Vector

Exploitation requires local access to the host running IBM Concert. The attacker leverages the uncontrolled recursive copy to transfer sensitive files into a directory they can read. Because no privileges or user interaction are required, any local account that can trigger the copy routine can obtain sensitive data. The IBM advisory listed above provides the authoritative description of the affected code path.

Detection Methods for CVE-2026-6544

Indicators of Compromise

Unexpected copies of configuration files, private keys, or credential stores appearing in Concert working directories
File access audit records showing Concert processes reading files outside expected application paths
Growth in Concert destination directories inconsistent with normal application artifact sizes

Detection Strategies

Enable Linux auditd rules on IBM Concert working directories to log file creation and read events
Compare directory inventories before and after Concert copy operations to flag unintended file inclusion
Review Concert application logs for recursive copy invocations and the paths they touched

Monitoring Recommendations

Monitor file system events for Concert processes accessing paths outside documented application directories
Alert on reads of sensitive file types such as .pem, .key, id_rsa, and .env by the Concert service account
Track permission changes on Concert destination directories to detect weakening of access controls

How to Mitigate CVE-2026-6544

Immediate Actions Required

Apply the IBM-provided fix referenced in the IBM Support Document
Inventory IBM Concert deployments and identify instances running versions 1.0.0 through 3.0.0
Audit directories that Concert reads from or writes to for sensitive files that should be relocated

Patch Information

IBM has published remediation guidance in the IBM Support Document. Administrators should upgrade IBM Concert to the fixed release identified in that advisory. Verify the installed version after upgrade and confirm that recursive copy operations now respect the documented controls.

Workarounds

Restrict local access to systems running IBM Concert using operating system account controls
Relocate sensitive files such as keys, credentials, and configuration secrets outside directories that Concert traverses
Apply strict file permissions on Concert destination directories to limit read access to authorized accounts
Isolate Concert workloads on hosts dedicated to the application to reduce exposure of unrelated sensitive data

bash

# Configuration example
# Restrict read access on IBM Concert destination directories
chown -R concert:concert /opt/ibm/concert/work
chmod -R 750 /opt/ibm/concert/work

# Example auditd rule to monitor sensitive file reads by Concert
auditctl -w /etc/ssl/private -p r -k concert_sensitive_read
auditctl -w /root/.ssh -p r -k concert_sensitive_read