CVE-2026-22864
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2026-01-15

Last updated on: 2026-01-15

Assigner: GitHub, Inc.

Description
Deno is a JavaScript, TypeScript, and WebAssembly runtime. Before 2.5.6, a prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path’s extension matched .bat or .cmd. That check performs a case-sensitive comparison against lowercase literals and therefore can be bypassed when the extension uses alternate casing (for example .BAT, .Bat, etc.). This vulnerability is fixed in 2.5.6.
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Meta Information
Published
2026-01-15
Last Modified
2026-01-15
Generated
2026-06-16
AI Q&A
2026-01-16
EPSS Evaluated
2026-06-15
NVD
CVE-2026-22864
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
denoland deno to 2.5.6 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-77 The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.
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Executive Summary

This vulnerability in Deno versions prior to 2.5.6 is a command injection issue on Windows systems. A prior patch tried to block spawning Windows batch or shell files by checking if the file extension was '.bat' or '.cmd' using a case-sensitive comparison against lowercase literals. However, this check could be bypassed by using alternate casing in the file extension (e.g., '.BAT', '.Bat'), allowing malicious batch scripts to be executed. This means attackers could run arbitrary commands by exploiting this casing bypass. [2]

Impact Analysis

This vulnerability allows remote attackers to perform command injection on affected Deno versions without requiring privileges or user interaction. Exploiting it can lead to execution of arbitrary commands, potentially compromising the confidentiality, integrity, and availability of the system running Deno. This high severity impact means attackers could take control of the system or disrupt its operation. [2]

Detection Guidance

You can detect this vulnerability by checking if your Deno installation version is prior to 2.5.6. Additionally, you can test if spawning batch files with alternate casing extensions (e.g., .BAT, .Bat) is possible. For example, attempt to spawn a command like './test.BAT' that executes a harmless command such as 'calc.exe' on Windows. If this executes, your system is vulnerable. [2]

Mitigation Strategies

The immediate step to mitigate this vulnerability is to upgrade Deno to version 2.5.6 or later, which includes a fix that enforces case-insensitive checks on batch file extensions to block execution regardless of casing. [2]

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