CVE-2025-43853: iwasm vulnerable to filesystem sandbox escape with symlink when using uvwasi feature
The WebAssembly Micro Runtime's (WAMR) iwasm package is the executable binary built with WAMR VMcore which supports WebAssembly System Interface (WASI) and command line interface. Anyone running WAMR up to and including version 2.2.0 or WAMR built with libc-uvwasi on Windows is affected by a symlink following vulnerability. On WAMR running in Windows, creating a symlink pointing outside of the preopened directory and subsequently opening it with create flag will create a file on host outside of the sandbox. If the symlink points to an existing host file, it's also possible to open it and read its content. Version 2.3.0 fixes the issue.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-43853?
CVE-2025-43853 has been classified as a critical vulnerability due to its potential to allow unauthorized access and code execution.
How do I fix CVE-2025-43853?
To fix CVE-2025-43853, upgrade the WebAssembly Micro Runtime iwasm to version 2.2.1 or later.
What systems are impacted by CVE-2025-43853?
CVE-2025-43853 affects all users running WebAssembly Micro Runtime iwasm version 2.2.0 or earlier built with libc-uvwasi on Windows.
What vulnerabilities does CVE-2025-43853 exploit?
CVE-2025-43853 exploits vulnerabilities in the WebAssembly System Interface support, enabling potential remote code execution.
When was CVE-2025-43853 disclosed?
CVE-2025-43853 was disclosed in 2025 and pertains to security issues in the WebAssembly Micro Runtime.