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 versions before 2.7.10 related to improper neutralization of special elements in OS commands (CWE-78). Specifically, the escapeShellArg() helper used in node:child_process when shell: true was set did not correctly quote arguments on Windows, failing to neutralize cmd.exe metacharacters and the % character. This flaw allows an attacker who controls any part of the argument passed to spawn/spawnSync/exec to inject additional arbitrary commands executed by cmd.exe. The issue is resolved 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, indicating high severity.
Mitigation Recommendations
Upgrade to Deno version 2.7.10 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Users should avoid using shell: true with untrusted input until patched.
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 versions before 2.7.10 related to improper neutralization of special elements in OS commands (CWE-78). Specifically, the escapeShellArg() helper used in node:child_process when shell: true was set did not correctly quote arguments on Windows, failing to neutralize cmd.exe metacharacters and the % character. This flaw allows an attacker who controls any part of the argument passed to spawn/spawnSync/exec to inject additional arbitrary commands executed by cmd.exe. The issue is resolved 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, indicating high severity.
Mitigation Recommendations
Upgrade to Deno version 2.7.10 or later, where this vulnerability is fixed. No other official remediation or temporary fixes are documented. Users should avoid using shell: true with untrusted input until patched.
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: 06/23/2026, 17:54:16 UTC
Last updated: 06/23/2026, 18:09:39 UTC
Views: 3
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