GHSA-m3c4-prhw-mrx6 — high GitHub Advisory (CVE-2026-22864) in rust/deno

Description

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(&#x27;./test.BAT&#x27;, {
  args: [&#x27;&amp;calc.exe&#x27;],
});
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:
photo_2025-10-10 02 27 23

Bypass of the patched vulnerability:
photo_2025-10-10 02 27 25

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.

Basic information

Type: reviewed
Severity: high
Advisory on GitHub: Open advisory ↗
Repository advisory: Open repository advisory ↗
Source code: Browse source ↗
Published (advisory): 2026-01-16 15:49:38 UTC
Updated: 2026-01-27 16:49:29 UTC
GitHub reviewed: 2026-01-16 15:49:38 UTC
NVD published: 2026-01-15

Score	Percentile
0.03%	8.64%

CVSS Scores

Base score	Version	Severity	Vector
8.1	3.1	—	`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type	Value
GHSA	GHSA-m3c4-prhw-mrx6 ↗
CVE	CVE-2026-22864 ↗

CWEs

CWE id	Name
CWE-77	Improper Neutralization of Special Elements used in a Command ('Command Injection')

Credits

SharokhAtaie (reporter)
B14CK-SPID3R (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem	Package	Vulnerable range	First patched	Vulnerable functions
rust	deno	< 2.5.6	2.5.6	—

Deno has an incomplete fix for command-injection prevention on Windows — case-insensitive extension bypass