CVE-2025-12767: IBM Concert DOS Vulnerability

CVE-2025-12767 Overview

CVE-2025-12767 is a denial of service vulnerability in IBM Concert versions 1.0.0 through 3.0.0. A remote, unauthenticated attacker can submit a specially crafted regular expression that triggers excessive resource consumption on the server. The flaw is tracked under [CWE-770: Allocation of Resources Without Limits or Throttling]. Successful exploitation degrades availability of the affected Concert instance without impacting confidentiality or integrity. IBM has published guidance in the IBM Support Page for Node 7288830.

Critical Impact
A remote attacker can exhaust CPU and memory resources on IBM Concert instances by submitting crafted regex input, degrading service availability for legitimate users.

Affected Products

IBM Concert 1.0.0
IBM Concert 2.x
IBM Concert 3.0.0

Discovery Timeline

2026-09-22 - CVE-2025-12767 published to the National Vulnerability Database (NVD)
2026-09-23 - Last updated in NVD database

Technical Details for CVE-2025-12767

Vulnerability Analysis

The vulnerability is a Regular Expression Denial of Service (ReDoS) condition in IBM Concert. Concert processes user-supplied input that is evaluated against or as a regular expression. When the regex engine encounters pathological patterns, backtracking or state expansion grows non-linearly with input size. This causes CPU utilization to spike and worker threads to stall. Because the attack vector is the network and no authentication is required, any reachable Concert endpoint can be targeted. The impact is limited to availability; the flaw does not expose data or allow code execution.

Root Cause

The underlying weakness is classified as [CWE-770: Allocation of Resources Without Limits or Throttling]. IBM Concert does not enforce sufficient bounds on regex complexity, evaluation time, or CPU consumption during pattern processing. A single crafted pattern can consume disproportionate resources, blocking legitimate request handling.

Attack Vector

Exploitation requires only network access to the vulnerable IBM Concert interface. The attacker submits a request containing a maliciously constructed regular expression or input designed to trigger catastrophic backtracking. Repeated submissions amplify the effect and can render the service unresponsive.

No verified proof-of-concept code is publicly available for this issue. Refer to the IBM Support Page for Node 7288830 for vendor-supplied technical detail.

Detection Methods for CVE-2025-12767

Indicators of Compromise

Sustained high CPU utilization on IBM Concert application processes without a corresponding legitimate workload increase.
Concert request logs showing unusually long-running requests or timeouts tied to endpoints that accept regex or pattern input.
Repeated inbound requests from a small set of source IPs containing complex or nested quantifier patterns.

Detection Strategies

Baseline normal CPU, memory, and request-duration metrics for Concert workloads and alert on statistical deviations.
Inspect HTTP request bodies for regex patterns containing nested quantifiers such as (a+)+, (.*)*, or long alternations before they reach the Concert service.
Correlate application performance degradation with inbound traffic bursts from the same client or user agent.

Monitoring Recommendations

Forward Concert application logs, web server access logs, and host telemetry to a centralized analytics platform for correlation.
Track per-endpoint request latency percentiles and alert on p95 or p99 latency spikes.
Monitor thread pool saturation and rejected requests as leading indicators of resource exhaustion.

How to Mitigate CVE-2025-12767

Immediate Actions Required

Review the IBM Support Page for Node 7288830 and apply the vendor-supplied fix for IBM Concert 1.0.0 through 3.0.0.
Inventory all Concert deployments and confirm each instance is within the affected version range.
Restrict network exposure of Concert management and API endpoints to trusted networks only.

Patch Information

IBM has published remediation guidance for CVE-2025-12767 on the IBM Support Page for Node 7288830. Administrators should follow IBM's version-specific upgrade instructions to remove the vulnerable regex handling behavior.

Workarounds

Place a reverse proxy or web application firewall in front of Concert to enforce request size limits and reject inputs containing high-risk regex constructs.
Apply rate limiting on endpoints that accept user-supplied patterns to reduce the impact of repeated abusive requests.
Restrict access to Concert to authenticated internal users where feasible until the patch is deployed.

bash

# Example NGINX rate limit and body size controls in front of IBM Concert
http {
    limit_req_zone $binary_remote_addr zone=concert_rl:10m rate=10r/s;

    server {
        listen 443 ssl;
        server_name concert.example.com;

        client_max_body_size 64k;

        location / {
            limit_req zone=concert_rl burst=20 nodelay;
            proxy_pass http://concert_backend;
        }
    }
}