CVE-2026-27190 is an OS command injection vulnerability identified in the Deno runtime, specifically within its node:child_process module implementation prior to version 2.6.8. Deno is a modern runtime for JavaScript, TypeScript, and WebAssembly, widely used for server-side and scripting applications. The vulnerability arises from improper neutralization of special characters or elements in inputs passed to OS commands, classified under CWE-78. This flaw allows an attacker to craft malicious inputs that are executed by the underlying operating system shell, enabling arbitrary command execution. The vulnerability does not require authentication or user interaction but has a high attack complexity, likely due to the need for specific conditions or input vectors. The CVSS v3.1 score of 8.1 reflects high impact on confidentiality, integrity, and availability, as arbitrary command execution can lead to data breaches, system compromise, or denial of service. Although no exploits have been reported in the wild yet, the widespread use of Deno in modern development environments makes this a critical issue. The fix was released in version 2.6.8, addressing the input sanitization and command invocation logic to prevent injection. Organizations using affected versions should prioritize upgrading and review any custom scripts or applications leveraging node:child_process to ensure inputs are properly sanitized and validated.

The impact of CVE-2026-27190 is significant for organizations using Deno runtime versions prior to 2.6.8. Successful exploitation allows remote attackers to execute arbitrary OS commands, potentially leading to full system compromise. This can result in unauthorized data access or exfiltration, modification or destruction of data, disruption of services, and lateral movement within networks. Given Deno's role in server-side applications and scripting, compromised systems could serve as entry points for broader attacks. The vulnerability affects confidentiality, integrity, and availability simultaneously, increasing risk severity. Organizations relying on cloud-native applications, microservices, or serverless functions built on Deno are particularly vulnerable. The lack of authentication or user interaction requirements lowers barriers for exploitation, although the high attack complexity may limit immediate widespread exploitation. Nonetheless, the potential damage to critical infrastructure, intellectual property, and customer data is substantial, warranting urgent remediation.

To mitigate CVE-2026-27190, organizations should immediately upgrade all Deno runtime instances to version 2.6.8 or later where the vulnerability is patched. Review and audit all code that invokes node:child_process or similar OS command execution interfaces to ensure inputs are strictly validated and sanitized, employing allowlists for acceptable characters and rejecting or escaping special shell metacharacters. Implement runtime application self-protection (RASP) or behavior monitoring to detect anomalous command execution patterns. Restrict permissions of processes running Deno to the minimum necessary, using containerization or sandboxing to limit potential damage from exploitation. Employ network segmentation and firewall rules to reduce exposure of vulnerable services. Additionally, maintain up-to-date intrusion detection and prevention systems (IDS/IPS) tuned to detect suspicious command injection attempts. Educate developers on secure coding practices related to OS command execution and input handling within Deno and JavaScript/TypeScript environments. Finally, monitor security advisories for any emerging exploit reports or additional patches.