CVE-2024-51745: Wasmtime Filesystem Sandbox Bypass via Superscript Device Filenames
Summary
CVE-2024-51745: Wasmtime doesn't fully sandbox all the Windows device filenames. Affects wasmtime across 3 version ranges.
< 24.0.2
>= 25.0.0, < 25.0.3
>= 26.0.0, < 26.0.1
Fixed in 24.0.2, 25.0.3 or 26.0.1, depending on the release line you run. How to fix ↓
Also tracked for
- rust-wasmtime · Debian:13
The same CVE-2024-51745 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Wasmtime is a runtime for WebAssembly that allows developers to execute WebAssembly programs in a secure environment. It provides a sandboxed execution model, ensuring that untrusted code cannot access sensitive system resources. However, its filesystem sandbox implementation on Windows has a critical flaw that allows certain device filenames to bypass the intended restrictions.
Vulnerability Detail
The vulnerability arises from Wasmtime's incomplete blocking of special device filenames on Windows. While it successfully restricts access to standard device names like 'COM1' and 'LPT0', it fails to block their superscript variants, such as 'COM¹' and 'LPT⁰'. This oversight allows untrusted WebAssembly programs to access peripheral devices connected to the system, including modems and printers, potentially leading to unauthorized access to sensitive hardware resources.
How To Fix
Latest published version: 50.0.0 as of 22 Oct 2026
Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 24.0.224.0.2 -
>= 25.0.0, < 25.0.325.0.3 -
>= 26.0.0, < 26.0.126.0.1
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
There are no known workarounds for this issue. Affected Windows users are strongly recommended to upgrade to the patched versions of Wasmtime.
Conclusion
The vulnerability CVE-2024-51745 in Wasmtime poses a significant risk by allowing untrusted WebAssembly programs to access sensitive device filenames on Windows. Users are strongly advised to upgrade to the latest patched versions to secure their systems against potential unauthorized access.
See every vulnerability recorded for wasmtime →
FAQ
CVE-2024-51745 is a vulnerability in Wasmtime that allows untrusted WebAssembly programs to bypass filesystem sandbox restrictions on Windows, potentially accessing sensitive peripheral devices.
If you are using an affected version of Wasmtime on Windows, untrusted WebAssembly programs could gain unauthorized access to devices like printers and modems, posing a security risk.
Wasmtime versions prior to 24.0.2, 25.0.3, and 26.0.1 are affected by this vulnerability.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. You can check if your application is affected by this vulnerability using the Vulert playground at Vulert Scanner without needing to sign up.
Currently, there are no known workarounds to mitigate this issue. The best course of action is to upgrade to a patched version of Wasmtime.
References
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