CVE-2026-22864 is a command injection vulnerability classified under CWE-77 affecting the Deno runtime environment before version 2.5.6. Deno, a runtime for JavaScript, TypeScript, and WebAssembly, includes functionality to spawn child processes. To mitigate risks, a prior patch attempted to block execution of Windows batch and shell files by checking the file extension against lowercase '.bat' and '.cmd'. However, this check was case-sensitive and did not account for alternate casing variations such as '.BAT' or '.Bat', allowing attackers to bypass the restriction. This improper neutralization of special elements in command execution enables an unauthenticated attacker to execute arbitrary commands remotely by supplying a path with a differently cased batch file extension. The vulnerability affects all Deno versions prior to 2.5.6 and impacts Windows environments where batch files are relevant. Exploitation can lead to full compromise of the host system, affecting confidentiality, integrity, and availability. The CVSS v3.1 score is 8.1 (High), indicating network attack vector, high impact, no privileges or user interaction required, but with high attack complexity due to the need to craft specific file paths. No known exploits are reported in the wild yet, but the vulnerability's nature and ease of bypass make it a critical risk for organizations using vulnerable Deno versions. The fix involves upgrading to Deno 2.5.6, which implements a case-insensitive check to properly block batch file execution regardless of casing.

For European organizations, the impact of CVE-2026-22864 is significant, especially for those leveraging Deno in development, automation, or server-side scripting on Windows platforms. Successful exploitation allows remote attackers to execute arbitrary commands without authentication, potentially leading to full system compromise. This threatens the confidentiality of sensitive data, integrity of applications and systems, and availability of critical services. Organizations relying on Deno for cloud-native applications, CI/CD pipelines, or internal tooling may face operational disruptions and data breaches. The vulnerability could be exploited to deploy malware, ransomware, or pivot within networks. Given the high CVSS score and no requirement for user interaction, the risk of automated exploitation attempts is high once public proof-of-concept code becomes available. European entities in finance, healthcare, and government sectors, which often use Windows-based infrastructure and have stringent data protection requirements, are particularly vulnerable to reputational and regulatory consequences if exploited.

To mitigate CVE-2026-22864, European organizations should immediately upgrade all Deno installations to version 2.5.6 or later, where the case-insensitive extension check is properly implemented. Additionally, organizations should audit scripts and tooling that spawn child processes to ensure they do not rely on vulnerable Deno versions or unsafe command execution patterns. Implement strict input validation and sanitization for any user-supplied data used in command spawning. Employ application whitelisting to restrict execution of unauthorized batch or shell scripts. Monitor logs for suspicious process spawning activities, especially those involving batch files with unusual casing. Network segmentation and endpoint protection can limit lateral movement if exploitation occurs. Finally, maintain up-to-date asset inventories to identify all Deno runtime deployments across Windows environments and apply patches promptly. Security teams should prepare incident response plans for potential exploitation scenarios involving command injection.