CVE-2024-51451 is a vulnerability identified in IBM Concert versions 1.0.0 through 2.1.0, stemming from improper neutralization of HTTP headers, specifically the HOST header, classified under CWE-644. The vulnerability arises because the application fails to properly validate or sanitize the HOST header input, allowing an attacker to inject malicious content into HTTP headers. This injection can be leveraged to conduct cross-site scripting (XSS) attacks, where malicious scripts execute in the context of the victim’s browser, potentially stealing session tokens or performing unauthorized actions. Additionally, attackers can exploit this flaw to poison caches, causing users to receive malicious or stale content, or hijack sessions by manipulating header data to bypass authentication controls. The vulnerability is remotely exploitable over the network without requiring privileges or user interaction, increasing its risk profile. Although no public exploits are currently known, the vulnerability’s nature and medium CVSS score (6.5) indicate a significant risk if weaponized. The flaw affects confidentiality and integrity but does not impact availability. IBM Concert is an enterprise collaboration and communication platform used in various sectors, making this vulnerability relevant for organizations relying on it for internal or external communications.

For European organizations, exploitation of CVE-2024-51451 could lead to unauthorized disclosure of sensitive information through XSS attacks, undermining confidentiality. Cache poisoning could disrupt content delivery, causing users to receive manipulated or malicious data, damaging trust and operational integrity. Session hijacking could allow attackers to impersonate legitimate users, leading to unauthorized access to internal resources or sensitive communications. These impacts are particularly critical for sectors handling personal data under GDPR, as breaches could result in regulatory penalties and reputational damage. Organizations using IBM Concert for critical communications or collaboration may face operational disruptions and increased risk of lateral movement by attackers. The vulnerability’s remote exploitability without authentication heightens the threat, especially in environments exposed to the internet or with insufficient network segmentation. The absence of known exploits provides a window for proactive mitigation but also underscores the need for vigilance.

European organizations should immediately assess their IBM Concert deployments to identify affected versions (1.0.0 through 2.1.0). In the absence of an official patch, implement strict input validation and sanitization on HTTP headers at the application or reverse proxy level to neutralize malicious payloads. Deploy Web Application Firewalls (WAFs) with custom rules to detect and block anomalous HOST header values indicative of injection attempts. Monitor HTTP traffic logs for unusual header patterns or repeated injection attempts to enable early detection. Network segmentation should be enforced to limit exposure of IBM Concert servers to untrusted networks. Educate security teams about this vulnerability to enhance incident response readiness. Coordinate with IBM support for updates or patches and plan timely upgrades to fixed versions once available. Additionally, conduct regular security assessments and penetration tests focusing on header injection vectors to validate mitigation effectiveness.