CVE-2026-4405 in Concert
Summary
by MITRE • 10/19/2026
IBM Concert 1.0 through 3.0.0 allows web page cache to be stored locally which can be read by another user on the system.
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Analysis
by VulDB Data Team • 10/19/2026
The vulnerability identified in IBM Concert versions 1.0 through 3.0.0 represents a significant information disclosure risk stemming from improper handling of local storage mechanisms within the application's architecture. Specifically, the software is designed to cache web pages locally on the client machine to improve performance and reduce network latency for subsequent requests. However, this caching implementation fails to enforce appropriate access controls or isolation boundaries between different user contexts on the same operating system instance. As a result, sensitive data contained within these cached web pages remains accessible in plaintext format to any other authenticated user who gains access to the local file system of the machine where IBM Concert is installed. This flaw effectively bypasses standard session management and authentication checks that would normally protect such information during active network transmission or server-side processing.
From a technical perspective, this issue aligns with CWE-200, which classifies as Exposure of Sensitive Information to an Unauthorized Actor. The root cause lies in the application's reliance on local disk storage without implementing file-level permissions or encryption that would restrict access based on user identity. In many operating systems, default directory structures for web caches are often world-readable or accessible by any process running under a standard user account if not explicitly secured. When IBM Concert writes cached content to these locations, it does not verify the security context of the writing process nor does it apply restrictive file attributes that would prevent other local users from reading those files. This creates a persistent storage vulnerability where data remains on disk long after the session has ended, providing an extended window of opportunity for exploitation by malicious insiders or attackers who have achieved limited access to the system.
The operational impact of this vulnerability is primarily centered around confidentiality loss rather than integrity or availability. An attacker with local access can enumerate cache directories and extract cached web pages that may contain sensitive business logic, internal URLs, user-specific data, or even authentication tokens if they were inadvertently included in the page content. This information can be leveraged for further reconnaissance activities, such as mapping out application endpoints or understanding how specific features function internally. In environments where multiple users share a single workstation or virtual machine, this flaw allows lateral movement of sensitive context from one user's session to another without requiring elevated privileges on the target account itself. The severity is heightened in corporate settings where shared computing resources are common and strict data segregation between employees is required for compliance purposes.
This vulnerability also maps directly to MITRE ATT&CK technique T1530, Data from Local System, specifically under the sub-technique of Data from Cloud Storage or local file systems depending on implementation details. It reflects a failure in secure coding practices regarding sensitive data retention and storage hygiene. The persistence of this cached data means that even if users log out properly, their session artifacts remain vulnerable to extraction by subsequent users logging into the same machine. This is particularly dangerous for applications handling proprietary information or regulated data where local caching might be enabled by default without administrator awareness of the security implications.
To mitigate this vulnerability, organizations should prioritize upgrading IBM Concert to a version later than 3.0.0 where these storage mechanisms have been corrected with proper access controls. If immediate patching is not feasible, administrators can implement compensating controls at the operating system level by restricting permissions on the specific directories used for caching web pages. This involves setting file system ACLs that limit read and write access to only the primary user account running the application service or process. Additionally, configuring the application to disable local caching entirely if it is not strictly required for business operations can eliminate the attack surface associated with this flaw. Regular audits of cached data locations should be conducted to ensure no sensitive information persists in accessible formats after sessions conclude.