CVE-2021-42777 is a critical remote code execution vulnerability affecting Stimulsoft Reports version 2013.1.1600.0 when operating in Compilation Mode. Stimulsoft Reports is a reporting tool that allows dynamic report generation, often used in enterprise environments for data visualization and reporting. The vulnerability arises because the product permits the execution of arbitrary C# code embedded within reports during the compilation process. An attacker who can supply or manipulate report content can exploit this flaw to execute arbitrary code on any machine that renders the report, including both application servers and end-user local machines. This execution capability is demonstrated by the ability to invoke System.Diagnostics.Process.Start, which can launch arbitrary processes. The vulnerability has a CVSS 3.1 base score of 9.8, indicating critical severity, with attack vector being network-based, no privileges or user interaction required, and full impact on confidentiality, integrity, and availability. No patches or vendor mitigations are currently listed, and no known exploits in the wild have been reported. The CWE-209 tag indicates that the vulnerability may also involve information exposure through error messages, but the primary risk is arbitrary code execution via report compilation. This vulnerability poses a significant risk to any organization using the affected Stimulsoft Reports version, especially if reports can be influenced by untrusted sources or users.

For European organizations, the impact of this vulnerability can be severe. Organizations relying on Stimulsoft Reports for business-critical reporting may face complete system compromise if an attacker exploits this vulnerability. Since the code execution can occur on application servers, attackers could gain persistent access to backend systems, exfiltrate sensitive data, disrupt services, or move laterally within the network. If reports are rendered on user endpoints, attackers could compromise individual machines, potentially leading to credential theft or further network intrusion. The lack of required authentication or user interaction means that exploitation can be fully remote and automated, increasing the risk of widespread attacks. Given the criticality of the vulnerability and the potential for full system compromise, affected organizations could face operational disruption, data breaches, regulatory penalties under GDPR, and reputational damage. The absence of known exploits in the wild may reduce immediate risk but also suggests that organizations should proactively address the vulnerability before attackers develop weaponized exploits.

1. Immediate mitigation should include disabling Compilation Mode in Stimulsoft Reports if feasible, to prevent execution of embedded C# code during report rendering. 2. Restrict report content creation and modification privileges strictly to trusted users and validate all report inputs to prevent injection of malicious code. 3. Implement network segmentation and application whitelisting on servers running Stimulsoft Reports to limit the impact of potential exploitation. 4. Monitor logs and network traffic for unusual process creation or suspicious activity related to report rendering services. 5. If possible, upgrade to a newer, patched version of Stimulsoft Reports once available or contact the vendor for official patches or workarounds. 6. Employ endpoint detection and response (EDR) solutions to detect and block unauthorized process execution on user machines. 7. Conduct security awareness training for users who interact with reports to recognize suspicious behavior. These steps go beyond generic advice by focusing on configuration changes, access controls, and proactive monitoring tailored to the nature of this vulnerability.