CVE-2025-43853: bytecodealliance wasm-micro-runtime UNIX Symbolic Link (Symlink) Following

Vulnerability summary

CVE-2025-43853 is a high (CVSS 7.0) UNIX Symbolic Link (Symlink) Following vulnerability in bytecodealliance wasm-micro-runtime. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.5% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 15-05-2025
   PublishedVulnerability first disclosed.
2. 15-05-2025
   Last modifiedVulnerability information updated.

Description

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.

• CWE-61UNIX Symbolic Link (Symlink) FollowingThe product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.