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Vulnerability record · CVE-2025-43853 · published 15 May 2025

CVE-2025-43853: Bytecodealliance webassembly micro runtime vulnerability

Bytecodealliance · Webassembly Micro Runtime

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.

7.0 CVSS 4.0 High EPSS 0.28% · top 81.6% CWE-61 · CWE-61
7.0CVSS 4.0 base score
0.28%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
17 Jun 2026Last modified by NVD

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.

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/bytecodealliance/wasm-micro-runtime/commit/28702edaf739cdeee54e81efe5868bf00724c33c Patch
https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-8fc8-4g25-c8m7 ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-43853), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.