CVE-2025-36243: IBM Concert SSRF Vulnerability

CVE-2025-36243 Overview

IBM Concert versions 1.0.0 through 2.1.0 contain a server-side request forgery (SSRF) vulnerability that allows authenticated attackers to send unauthorized requests from the system. This security flaw can potentially enable network enumeration or serve as a stepping stone for launching additional attacks against internal infrastructure.

Critical Impact

Authenticated attackers can leverage this SSRF vulnerability to bypass network security controls, enumerate internal services, and potentially pivot to attack internal systems that would otherwise be inaccessible from external networks.

Affected Products

• IBM Concert 1.0.0
• IBM Concert versions through 2.1.0
• All IBM Concert deployments within the affected version range

Discovery Timeline

• 2026-02-17 - CVE-2025-36243 published to NVD
• 2026-02-18 - Last updated in NVD database

Technical Details for CVE-2025-36243

Vulnerability Analysis

This vulnerability is classified as CWE-918: Server-Side Request Forgery (SSRF). SSRF vulnerabilities occur when an application can be tricked into making HTTP requests to an arbitrary domain or IP address chosen by an attacker. In the context of IBM Concert, authenticated users can manipulate request parameters to cause the server to initiate connections to unintended destinations.

The vulnerability requires authentication (low privileges), which provides some barrier to exploitation, but once an attacker has valid credentials, they can exploit this flaw to probe internal network resources, access cloud metadata services, or interact with internal APIs that are not exposed to external networks.

Root Cause

The root cause of this SSRF vulnerability lies in insufficient validation of user-supplied URLs or hostnames within IBM Concert's server-side request handling logic. When the application processes requests that include external resource references, it fails to properly validate or restrict the destination of these server-initiated requests. This allows authenticated users to specify arbitrary internal or external targets, bypassing network segmentation and firewall controls.

Attack Vector

The attack is network-based and requires low-privilege authentication to exploit. An authenticated attacker can craft malicious requests containing URLs pointing to internal services, cloud metadata endpoints (such as 169.254.169.254 for AWS), or other sensitive internal resources.

The exploitation process typically involves:

1. Authenticating to IBM Concert with valid credentials
2. Identifying input fields or API endpoints that trigger server-side requests
3. Manipulating these inputs to specify internal IP addresses, localhost services, or cloud metadata endpoints
4. Analyzing response data to enumerate internal services or extract sensitive information

This vulnerability could enable attackers to scan internal network ports, access cloud instance metadata containing credentials, or interact with internal services that trust requests originating from the IBM Concert server.

Detection Methods for CVE-2025-36243

Indicators of Compromise

• Unusual outbound HTTP/HTTPS requests from IBM Concert servers to internal IP ranges (e.g., 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16)
• Requests to cloud metadata endpoints such as 169.254.169.254 or metadata.google.internal
• Anomalous connection attempts to localhost services (127.0.0.1) from the application
• High volume of requests to various internal ports from IBM Concert processes

Detection Strategies

• Implement network monitoring to detect outbound connections from IBM Concert servers to internal IP ranges that should not be accessed
• Configure web application firewalls (WAF) to detect and block SSRF patterns in request parameters
• Enable verbose logging on IBM Concert to capture all outbound request URLs for forensic analysis
• Deploy intrusion detection rules to alert on requests to cloud metadata endpoints from application servers

Monitoring Recommendations

• Monitor egress traffic from IBM Concert servers for connections to unexpected internal destinations
• Implement alerting for any requests to RFC 1918 private IP ranges or link-local addresses
• Review authentication logs for accounts exhibiting unusual request patterns that may indicate SSRF exploitation attempts
• Correlate IBM Concert application logs with network flow data to identify potential reconnaissance activity

How to Mitigate CVE-2025-36243

Immediate Actions Required

• Review and restrict network access from IBM Concert servers to only necessary external destinations
• Implement network segmentation to limit the impact of potential SSRF exploitation
• Audit user accounts with access to IBM Concert and enforce principle of least privilege
• Apply the security patch from IBM as soon as possible

Patch Information

IBM has released a security advisory addressing this vulnerability. Organizations should consult the IBM Support Page for detailed patch information and upgrade instructions. It is strongly recommended to upgrade IBM Concert to a patched version that addresses CVE-2025-36243.

Workarounds

• Implement strict egress filtering to block IBM Concert servers from initiating connections to internal networks or sensitive endpoints
• Deploy a web application firewall with SSRF protection rules to filter malicious request patterns
• Configure network-level controls to prevent access to cloud metadata services from application servers
• Implement URL allowlisting for any server-side request functionality, restricting destinations to known-safe domains only

Organizations should apply the vendor-provided patch as soon as feasible, as workarounds may not provide complete protection against all exploitation scenarios. Regular security assessments and monitoring should be conducted to detect potential exploitation attempts.