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.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-m3c4-prhw-mrx6 Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 21 Jan 2026 23:45:00 +0900

Type Values Removed Values Added
CPEs cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*

Sat, 17 Jan 2026 03:15:00 +0900

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Fri, 16 Jan 2026 23:15:00 +0900

Type Values Removed Values Added
First Time appeared Deno
Deno deno
Vendors & Products Deno
Deno deno

Fri, 16 Jan 2026 08:15:00 +0900

Type Values Removed Values Added
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.
Title Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass
Weaknesses CWE-77
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-01-16T17:16:02.143Z

Reserved: 2026-01-12T16:20:16.746Z

Link: CVE-2026-22864

cve-icon Vulnrichment

Updated: 2026-01-16T17:15:51.216Z

cve-icon NVD

Status : Analyzed

Published: 2026-01-15T23:15:51.937

Modified: 2026-01-21T14:32:39.837

Link: CVE-2026-22864

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-01-16T22:42:09Z

Weaknesses