CVE-2025-61787 is a command injection vulnerability classified under CWE-77, affecting the Deno runtime environment on Windows systems. Deno is a modern runtime for JavaScript, TypeScript, and WebAssembly, widely used for server-side scripting and automation. The vulnerability stems from how Windows handles batch file execution: when a batch file (.bat, .cmd) is executed, Windows' CreateProcess() API implicitly invokes cmd.exe, even if the application does not explicitly specify it. This behavior allows an attacker to inject malicious commands if untrusted input is passed to the batch file execution context within Deno. Specifically, versions of Deno prior to 2.5.3 and 2.2.15 are vulnerable when they execute batch files on Windows, enabling command injection without requiring authentication or user interaction. The CVSS v3.1 score of 8.1 reflects the high impact on confidentiality, integrity, and availability, with network attack vector and no privileges required. Although no known exploits have been reported in the wild, the vulnerability poses a significant risk due to the potential for remote code execution. The fix involves upgrading to patched versions 2.5.3 or 2.2.15, which address the improper neutralization of special elements in command execution. Organizations using Deno in Windows environments should review their code for batch file execution paths and sanitize inputs to prevent injection. This vulnerability highlights the risks of implicit OS behaviors in runtime environments and the importance of input validation when invoking system commands.

For European organizations, this vulnerability could lead to severe consequences including unauthorized remote code execution, data breaches, service disruption, and potential lateral movement within networks. Organizations using Deno on Windows for backend services, automation scripts, or CI/CD pipelines are particularly at risk. The compromise of such systems could expose sensitive data, intellectual property, and customer information, violating GDPR and other data protection regulations. Additionally, availability impacts could disrupt business operations and damage reputation. The high CVSS score indicates that exploitation could lead to full system compromise without requiring user interaction or authentication, increasing the threat level. Given the growing adoption of Deno in modern development stacks, especially in tech-forward European countries, the vulnerability could be leveraged by attackers targeting software supply chains or cloud infrastructure. The lack of known exploits in the wild suggests a window of opportunity for defenders to patch and mitigate before widespread attacks occur.

1. Immediately upgrade all Deno installations on Windows to versions 2.5.3 or 2.2.15 or later to apply the official patch. 2. Audit all codebases and scripts that invoke batch files or shell commands within Deno to ensure no untrusted input is passed without proper sanitization or escaping. 3. Implement strict input validation and use safe APIs that avoid shell invocation when possible. 4. Employ application whitelisting and endpoint protection solutions to detect and block suspicious command execution patterns. 5. Monitor logs for unusual cmd.exe invocations or batch file executions originating from Deno processes. 6. Restrict permissions for Deno runtime environments to minimize the impact of potential exploitation. 7. Educate developers about the risks of command injection and secure coding practices related to system command execution. 8. Consider isolating Deno workloads in containerized or sandboxed environments to limit lateral movement in case of compromise.