CVE-2026-49402: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in denoland deno
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:child_process implementation provided an escapeShellArg() helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.exe metacharacters and did not neutralize % (which cmd.exe expands even inside double-quoted strings). An attacker who controlled any portion of an argument passed to such a call could inject arbitrary additional commands into the spawned cmd.exe invocation. This vulnerability is fixed in 2.7.10.
AI Analysis
Technical Summary
Deno, a runtime for JavaScript, TypeScript, and WebAssembly, had a vulnerability (CVE-2026-49402) in its node:child_process module before version 2.7.10. The escapeShellArg() helper function failed to properly escape shell arguments on Windows, specifically not quoting cmd.exe metacharacters and not neutralizing the % character, which cmd.exe expands even inside double quotes. This improper neutralization of special elements (CWE-78) allows an attacker controlling any part of an argument passed to spawn, spawnSync, exec, or similar functions with shell: true to inject arbitrary commands into the cmd.exe invocation. The vulnerability is addressed in Deno 2.7.10.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary commands on the underlying Windows system via crafted arguments to child process calls with shell: true. This can lead to full compromise of confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 8.1 (High), reflecting network attack vector, high impact on confidentiality, integrity, and availability, and requiring no privileges or user interaction.
Mitigation Recommendations
Upgrade Deno to version 2.7.10 or later where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Until upgrading, avoid passing untrusted input to child process functions with shell: true on Windows.
CVE-2026-49402: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in denoland deno
Description
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.10, Deno's node:child_process implementation provided an escapeShellArg() helper used when callers passed shell: true to spawn / spawnSync / exec and friends. On Windows, the helper failed to quote arguments that contained cmd.exe metacharacters and did not neutralize % (which cmd.exe expands even inside double-quoted strings). An attacker who controlled any portion of an argument passed to such a call could inject arbitrary additional commands into the spawned cmd.exe invocation. This vulnerability is fixed in 2.7.10.
CVSS v3.1
Score 8.1high
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Deno, a runtime for JavaScript, TypeScript, and WebAssembly, had a vulnerability (CVE-2026-49402) in its node:child_process module before version 2.7.10. The escapeShellArg() helper function failed to properly escape shell arguments on Windows, specifically not quoting cmd.exe metacharacters and not neutralizing the % character, which cmd.exe expands even inside double quotes. This improper neutralization of special elements (CWE-78) allows an attacker controlling any part of an argument passed to spawn, spawnSync, exec, or similar functions with shell: true to inject arbitrary commands into the cmd.exe invocation. The vulnerability is addressed in Deno 2.7.10.
Potential Impact
Successful exploitation allows an unauthenticated attacker to execute arbitrary commands on the underlying Windows system via crafted arguments to child process calls with shell: true. This can lead to full compromise of confidentiality, integrity, and availability of the affected system. The CVSS v3.1 base score is 8.1 (High), reflecting network attack vector, high impact on confidentiality, integrity, and availability, and requiring no privileges or user interaction.
Mitigation Recommendations
Upgrade Deno to version 2.7.10 or later where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Until upgrading, avoid passing untrusted input to child process functions with shell: true on Windows.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-29T19:08:01.257Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a3ac4efeed863c81e618231
Added to database: 06/23/2026, 17:39:59 UTC
Last enriched: 06/30/2026, 23:13:27 UTC
Last updated: 08/04/2026, 12:46:13 UTC
Views: 54
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