CVE-2025-36161: IBM Concert Information Disclosure Flaw

CVE-2025-36161 Overview

CVE-2025-36161 affects IBM Concert versions 1.0.0 through 2.0.0. The application fails to properly enable the HTTP Strict-Transport-Security (HSTS) response header. A remote attacker positioned on the network path can exploit this weakness using man-in-the-middle (MITM) techniques. Without HSTS, browsers may downgrade connections to cleartext HTTP, exposing session data and sensitive information in transit. IBM published an advisory tracking the issue under support node 7252019. The weakness maps to [CWE-327]: Use of a Broken or Risky Cryptographic Algorithm, reflecting the reliance on insecure transport enforcement.

Critical Impact
Remote attackers can intercept sensitive IBM Concert traffic through connection downgrade and MITM attacks when HSTS is not enforced.

Affected Products

IBM Concert 1.0.0
IBM Concert versions between 1.0.0 and 2.0.0
IBM Concert 2.0.0

Discovery Timeline

2025-11-20 - CVE-2025-36161 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-36161

Vulnerability Analysis

IBM Concert serves web content over TLS but does not emit the Strict-Transport-Security response header. Browsers therefore do not receive instruction to enforce HTTPS on subsequent requests. This allows an attacker with a network foothold to strip TLS or force connection downgrades. The exposure targets confidentiality of session tokens, authentication cookies, and application data transmitted between clients and the Concert server. The EPSS score is 0.189% with an 8.652 percentile, indicating low observed exploitation activity, though the risk to sensitive workflows remains material.

Root Cause

The application server configuration omits the HSTS header from HTTPS responses. Without Strict-Transport-Security directives such as max-age and includeSubDomains, browsers do not pin future requests to HTTPS. The weakness is classified under [CWE-327] because it undermines the guarantees provided by TLS at the protocol enforcement layer.

Attack Vector

An attacker on the same network segment or in control of an upstream network device intercepts an initial cleartext request from a victim. The attacker proxies the connection, stripping TLS and relaying traffic to the legitimate Concert server. Because HSTS is not enforced, the victim's browser accepts the downgraded channel. Session cookies, credentials, and API payloads become visible to the attacker.

No verified public exploit code is available. Refer to the IBM Security Advisory for vendor-supplied technical details.

Detection Methods for CVE-2025-36161

Indicators of Compromise

Unexpected cleartext HTTP traffic to or from IBM Concert hosts that normally serve HTTPS.
Repeated TLS handshake anomalies or certificate mismatches originating from the Concert application URL.
Session reuse from geographically or network-distinct client IP addresses within short time windows.

Detection Strategies

Inspect HTTPS responses from Concert endpoints and flag any missing Strict-Transport-Security header on production hosts.
Correlate authentication events with connection metadata to identify sessions established over downgraded transport.
Deploy TLS inspection controls that alert on protocol downgrade attempts against internal IBM Concert URLs.

Monitoring Recommendations

Enable continuous scanning of internal web assets to verify HSTS enforcement and other transport security headers.
Monitor reverse proxy and load balancer logs for HTTP-to-HTTPS redirect patterns that indicate stripped connections.
Alert on anomalous user-agent activity accessing Concert over non-TLS ports.

How to Mitigate CVE-2025-36161

Immediate Actions Required

Apply the fix documented in the IBM Security Advisory for IBM Concert.
Enforce HTTPS-only access to Concert at the network edge and disable listeners on plain HTTP.
Rotate session tokens and credentials issued to Concert users during the exposure window.

Patch Information

IBM has published remediation guidance for IBM Concert versions 1.0.0 through 2.0.0. Administrators should review the vendor advisory at IBM Support Node 7252019 and upgrade to a fixed release that enables HSTS by default.

Workarounds

Configure the reverse proxy or ingress controller in front of IBM Concert to inject a Strict-Transport-Security header with an appropriate max-age.
Preload the Concert domain in the browser HSTS preload list when the deployment uses a dedicated hostname.
Restrict Concert access to VPN or zero-trust network access paths to reduce MITM exposure.

bash

# Example: adding HSTS at an NGINX reverse proxy fronting IBM Concert
add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;