# CVE-2024-27530: wasm3 pywasm3 use-after-free in ForEachModule

Source: https://junglewise.ai/threats/cve-2024-27530-wasm3-pywasm3-use-after-free-in-foreachmodule  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-11-09. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2024-27530 · Severity: high · CVSS 8.4 · Published 2024-11-09

pywasm3 is a Python wrapper for Wasm3, a fast WebAssembly interpreter used to run portable code across different platforms. A memory management flaw allows a specially crafted WebAssembly file to crash the application or potentially execute unauthorized code. This could lead to a complete loss of system confidentiality and availability if an attacker can convince a user or automated process to load a malicious file.

Technologies: [pywasm3 (PyPI)](https://junglewise.ai/threats/technologies/pywasm3). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2024-27530 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-27530 being exploited in the wild.

**How severe is CVE-2024-27530?** High severity, with a CVSS score of 8.4, published 9 November 2024.

**Which products and versions are affected?** pywasm3 (PyPI) <= 0.5.0, ECOSYSTEM:introduced=0,last_affected=0.5.0, ECOSYSTEM:introduced=0,last_affected=139076a.

**Is there a fix for CVE-2024-27530?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2024-27530 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2024-27530?** Check whether you run pywasm3 (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free (UAF) vulnerability exists in the ForEachModule function within m3_env.c of the Wasm3 interpreter (and its Python binding pywasm3). The flaw is triggered during module cleanup or when handling function signature mismatches, where the runtime attempts to access memory associated with a module that has already been freed. An attacker can exploit this by providing a malformed WebAssembly (.wasm) file. Successful exploitation can lead to arbitrary code execution or a denial-of-service (DoS) condition. The vulnerability was identified in commit 139076a and affects pywasm3 versions up to 0.5.0. No official patch was confirmed at the time of the advisory.

## Affected products

- wasm3 pywasm3 <= 0.5.0
- wasm3 wasm3 139076a

## Identifiers

- CVE-2024-27530
- GHSA-46r6-92jg-22jg
- PYSEC-2024-306

## Timeline

- 2024-02-05: disclosed: Issue reported on GitHub repository
- 2024-11-08: advisory: NVD published CVE-2024-27530
- 2024-11-09: advisory: GitHub Advisory GHSA-46r6-92jg-22jg published

## References

- [https://github.com/wasm3/wasm3/issues/458](https://github.com/wasm3/wasm3/issues/458)
- [https://gist.github.com/haruki3hhh/94dd274487b58e037bcc8839dc88b203](https://gist.github.com/haruki3hhh/94dd274487b58e037bcc8839dc88b203)
- [https://github.com/pypa/advisory-database/tree/main/vulns/pywasm3/PYSEC-2024-306.yaml](https://github.com/pypa/advisory-database/tree/main/vulns/pywasm3/PYSEC-2024-306.yaml)
- [https://github.com/wasm3/pywasm3/blob/main/wasm3/m3_env.c](https://github.com/wasm3/pywasm3/blob/main/wasm3/m3_env.c)

## Related threats

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- [wasm3 pywasm3 out-of-bounds read in m3_exec.h](https://junglewise.ai/threats/cve-2024-27528-wasm3-pywasm3-out-of-bounds-read-in-m3-exec-h)
- [Wasm3 uncontrolled memory allocation in Read_utf8](https://junglewise.ai/threats/cve-2024-27529-wasm3-uncontrolled-memory-allocation-in-read-utf8)
- [PYSEC-2024-303 - wasm3 139076a is vulnerable to Denial of Service (DoS).](https://junglewise.ai/threats/cve-2024-27527-pysec-2024-303-wasm3-139076a-is-vulnerable-to-denial-of-service)
- [PYSEC-2024-307 - wasm3 v0.5.0 was discovered to contain an out-of-bound memory read which leads to segmentation fault…](https://junglewise.ai/threats/cve-2024-34246-pysec-2024-307-wasm3-v0-5-0-was-discovered-to-contain-an-out-of)