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GHSA-m3c4-prhw-mrx6
No affected components available
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.
The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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