CVE-2025-43853
iwasm vulnerable to filesystem sandbox escape with symlink when using uvwasi feature
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.
INFO
Published Date :
May 15, 2025, 6:15 p.m.
Last Modified :
Sept. 19, 2025, 6:10 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update WAMR to version 2.3.0 or later.
- Review and secure symlink creation and usage.
- Verify file access controls in the runtime environment.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-43853.
| URL | Resource |
|---|---|
| https://github.com/bytecodealliance/wasm-micro-runtime/commit/28702edaf739cdeee54e81efe5868bf00724c33c | Patch |
| https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-8fc8-4g25-c8m7 | Exploit Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-43853 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-43853
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-43853 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-43853 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 19, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:bytecodealliance:webassembly_micro_runtime:*:*:*:*:*:*:*:* versions up to (excluding) 2.2.0 Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasm-micro-runtime/commit/28702edaf739cdeee54e81efe5868bf00724c33c Types: Patch Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-8fc8-4g25-c8m7 Types: Exploit, Third Party Advisory -
New CVE Received by [email protected]
May. 15, 2025
Action Type Old Value New Value Added 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. Added CVSS V4.0 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:X/V:X/RE:X/U:X Added CWE CWE-61 Added Reference https://github.com/bytecodealliance/wasm-micro-runtime/commit/28702edaf739cdeee54e81efe5868bf00724c33c Added Reference https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-8fc8-4g25-c8m7