CVE-2026-22864
HIGH
GHSA-m3c4-prhw-mrx6
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
4Description
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.
Analysis
Arbitrary code execution in Deno runtime versions before 2.5.6 allows unauthenticated attackers to bypass shell script execution restrictions by using alternate casing in batch file extensions (e.g., .BAT, .Bat instead of .bat). The case-sensitive validation flaw enables attackers to spawn blocked Windows batch and command files, achieving remote code execution. …
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Remediation
Within 7 days: Identify all affected systems and apply vendor patches promptly. Validate that input sanitization is in place for all user-controlled parameters.
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External POC / Exploit Code
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