CVE-2026-24656 is a critical security vulnerability classified under CWE-502, which involves the deserialization of untrusted data within the Apache Karaf Decanter log socket collector. Apache Karaf is a modular open-source OSGi runtime used for deploying containerized applications, and Decanter is an optional component that collects and processes log data. The vulnerability arises because the Decanter log socket collector exposes port 4560 without any authentication mechanism, allowing unauthenticated attackers to connect and send serialized data. Deserialization of untrusted data is dangerous because it can lead to arbitrary code execution, denial of service, or other malicious outcomes depending on the deserialized payload. In this case, the primary impact is a denial of service condition caused by processing crafted serialized objects. The vulnerability can be exacerbated if the 'allowed classes' property, which is intended to restrict deserialization to safe classes, is configured but can be bypassed by attackers. Since Decanter is not installed by default, only systems with this component explicitly enabled are vulnerable. The issue affects all versions of Apache Karaf Decanter prior to 2.12.0, which includes the affected versions before the patch. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The recommended remediation is to upgrade to Apache Karaf Decanter version 2.12.0, where this vulnerability has been addressed by implementing proper authentication and safer deserialization practices.

For European organizations using Apache Karaf with the Decanter component enabled, this vulnerability poses a risk of denial of service attacks that could disrupt critical logging and monitoring infrastructure. Since logging is essential for security monitoring, incident response, and compliance, disruption could delay detection of other attacks or system failures. Organizations in sectors such as finance, telecommunications, manufacturing, and government that rely on Apache Karaf for application deployment and monitoring could experience operational downtime or degraded service availability. The lack of authentication on the exposed port increases the attack surface, especially for systems accessible from less trusted networks. Although no remote code execution is confirmed, denial of service can still have significant operational and reputational impacts. The limited default installation of Decanter reduces the overall exposure, but targeted attacks against known deployments remain a concern. Additionally, the bypass of the 'allowed classes' property means that even hardened configurations may be vulnerable, increasing the risk. European organizations with strict uptime and compliance requirements may face regulatory scrutiny if logging systems are compromised or unavailable.

1. Immediately upgrade Apache Karaf Decanter to version 2.12.0 or later, which contains the fix for this vulnerability. 2. If upgrading is not immediately possible, disable the Decanter log socket collector component to eliminate exposure. 3. Restrict network access to port 4560 using firewall rules or network segmentation to limit connections only to trusted hosts. 4. Review and harden the 'allowed classes' deserialization property configuration to ensure it does not allow bypasses; consider disabling it if not required. 5. Monitor network traffic and logs for unusual connections or serialized payloads targeting port 4560. 6. Implement intrusion detection systems (IDS) or endpoint detection and response (EDR) solutions to detect exploitation attempts. 7. Conduct regular security assessments and penetration tests focusing on deserialization vulnerabilities in custom or third-party components. 8. Educate development and operations teams about the risks of deserialization of untrusted data and secure coding practices. 9. Maintain an inventory of Apache Karaf deployments to identify which systems have Decanter installed and prioritize remediation accordingly.