CVE-2022-39256 is a security vulnerability identified in Orckestra C1 CMS Foundation, a .NET-based Web Content Management System widely used for managing website content. The vulnerability is classified under CWE-502, which pertains to the deserialization of untrusted data. Specifically, versions of Orckestra C1 CMS prior to 6.13 are affected. The flaw allows an authenticated attacker to execute arbitrary code remotely by exploiting unsafe deserialization mechanisms within the CMS. This means that when the system processes serialized data from an untrusted source without proper validation or sanitization, it can lead to the execution of malicious payloads embedded within the serialized objects. The exploitation requires the attacker to have valid authentication credentials, but the attack can be triggered unknowingly by the authenticated user visiting a specially crafted malicious website, indicating a potential for social engineering or cross-site attack vectors. The vulnerability was publicly disclosed on September 27, 2022, and has been patched in version 6.13 of the software. No known workarounds exist, and there are no reports of active exploitation in the wild to date. The absence of a CVSS score necessitates an independent severity assessment based on the technical characteristics of the vulnerability.

For European organizations using Orckestra C1 CMS versions prior to 6.13, this vulnerability poses a significant risk. Successful exploitation could lead to remote code execution, compromising the confidentiality, integrity, and availability of the affected web servers and potentially the broader network environment. Attackers could gain control over the CMS, manipulate website content, steal sensitive data, deploy malware, or use the compromised system as a foothold for lateral movement within the organization. Given that authentication is required, the threat is somewhat mitigated by the need for valid credentials; however, the possibility of tricking authenticated users into visiting malicious sites increases the risk of exploitation. The impact is particularly critical for organizations that rely heavily on their web presence for business operations, customer engagement, or public communications, including e-commerce platforms, government portals, and media outlets. Additionally, the lack of workarounds means that organizations must apply the patch promptly to mitigate the risk. The vulnerability could also affect the availability of services if exploited to disrupt CMS operations or deploy ransomware.

European organizations should prioritize upgrading Orckestra C1 CMS installations to version 6.13 or later, where the vulnerability is patched. Since no workarounds exist, patching is the primary mitigation strategy. Additionally, organizations should enforce strict access controls and monitor authentication logs for unusual activity to detect potential misuse of valid credentials. Implementing multi-factor authentication (MFA) can reduce the risk of credential compromise. Web application firewalls (WAFs) should be configured to detect and block suspicious serialized data patterns or anomalous requests targeting the CMS. Security awareness training should be conducted to educate authenticated users about the risks of visiting untrusted or suspicious websites, reducing the likelihood of social engineering exploitation. Regular vulnerability scanning and penetration testing focused on CMS components can help identify unpatched instances. Finally, network segmentation can limit the impact of a compromised CMS server by restricting lateral movement within the internal network.