GHSA-M3C4-PRHW-MRX6
Vulnerability from github – Published: 2026-01-16 15:49 – Updated: 2026-01-16 15:49
VLAI
Summary
Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass
Details
Summary
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.).
POC
const command = new Deno.Command('./test.BAT', {
args: ['&calc.exe'],
});
const child = command.spawn();
This causes calc.exe to be launched; see the attached screenshot for evidence.
Patched in CVE-2025-61787 — prevents execution of .bat and .cmd files:
Bypass of the patched vulnerability:
Impact
The script launches calc.exe on Windows, demonstrating that passing user-controlled arguments to a spawned batch script can result in command-line injection.
Mitigation
Users should update to Deno v2.5.6 or newer.
Severity
8.1 (High)
{
"affected": [
{
"package": {
"ecosystem": "crates.io",
"name": "deno"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.5.6"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-22864"
],
"database_specific": {
"cwe_ids": [
"CWE-77"
],
"github_reviewed": true,
"github_reviewed_at": "2026-01-16T15:49:38Z",
"nvd_published_at": "2026-01-15T23:15:51Z",
"severity": "HIGH"
},
"details": "### Summary\nA prior patch aimed to block spawning Windows batch/shell files by returning an error when a spawned path\u2019s 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.).\n\n### POC\n```javascript\nconst command = new Deno.Command(\u0027./test.BAT\u0027, {\n args: [\u0027\u0026calc.exe\u0027],\n});\nconst child = command.spawn();\n```\nThis causes `calc.exe` to be launched; see the attached screenshot for evidence.\n\n**Patched in `CVE-2025-61787` \u2014 prevents execution of `.bat` and `.cmd` files:**\n\n\n**Bypass of the patched vulnerability:**\n\n\n\n### Impact\nThe script launches calc.exe on Windows, demonstrating that passing user-controlled arguments to a spawned batch script can result in command-line injection.\n\n### Mitigation\n\nUsers should update to Deno v2.5.6 or newer.",
"id": "GHSA-m3c4-prhw-mrx6",
"modified": "2026-01-16T15:49:38Z",
"published": "2026-01-16T15:49:38Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/denoland/deno/security/advisories/GHSA-m3c4-prhw-mrx6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-22864"
},
{
"type": "PACKAGE",
"url": "https://github.com/denoland/deno"
},
{
"type": "WEB",
"url": "https://github.com/denoland/deno/releases/tag/v2.5.6"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Deno has an incomplete fix for command-injection prevention on Windows \u2014 case-insensitive extension bypass"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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