CVE-2025-15666: Assimp Heap Buffer Overflow in Model File Handler

Technical summary

CVE-2025-15666 is a heap-based buffer overflow affecting Assimp::SceneCombiner::Copy in code/Common/SceneCombiner.cpp. The vulnerability stems from improper bounds checking on width and height arguments during model file processing. CWE-119 (improper restriction of operations within the bounds of a memory buffer) and CWE-122 (heap-based buffer overflow) classification indicates the flaw allows out-of-bounds memory writes. Attack vector is local (AV:L), access requires low privileges (PR:L), and no user interaction is needed (UI:N), resulting in a CVSS v3.1 score of 5.3 (MEDIUM). Public disclosure has occurred, and exploit code is available.

Business impact

Organizations embedding Assimp in applications—particularly 3D modeling tools, CAD software, game engines, or asset management platforms—face a localized attack surface. Exploitation could lead to code execution, privilege escalation, or denial of service if an attacker supplies a specially crafted model file. The impact is confined to systems where the application runs with user-level access and processes untrusted input, but the local nature and public exploit code elevate operational risk in multi-user or shared computing environments.

Affected systems

Assimp library versions up to and including 5.4.3 are affected. Any application or service that depends on Assimp for 3D model file parsing—including open-source projects, commercial software, and embedded systems—may be vulnerable if they have not updated past the affected versions. Applications running on systems with multiple user accounts or processing externally sourced model files are at higher risk.

Exploitability

The vulnerability is locally exploitable and requires the attacker to either have an interactive login session or the ability to run code on the target system. Public exploit code is available, removing the barrier to weaponization for threat actors with local system presence. However, the requirement for local access and low-level user privileges significantly constrains real-world exploitation compared to network-based vulnerabilities. The primary attack scenario involves a user opening a malicious .obj, .fbx, .dae, or other model file processed by Assimp.

Remediation

Patch Assimp to a version released after 5.4.3 that includes fixes for issue #6128. Verify the patch version against the official Assimp project repository and release notes. Organizations unable to patch immediately should restrict file upload sources, disable Assimp-dependent features where feasible, and monitor for suspicious local process behavior. Implement file validation and sandboxing for model file processing pipelines.

Patch guidance

Update Assimp to the latest stable release from the official repository (github.com/assimp/assimp). Version 5.4.3 and earlier are confirmed vulnerable; verify that your deployed version is later than 5.4.3 and includes the fix for issue #6128. If using Assimp as a vendored dependency, rebuild your application with the patched library version. Test compatibility in a staging environment before production deployment, as buffer overflow fixes may introduce behavioral changes in edge cases.

Detection guidance

Monitor application logs for crashes or memory access violations in Assimp components, particularly during model file import operations. Endpoint detection and response (EDR) tools should flag heap overflow attempts or unusual memory access patterns associated with Assimp processes. If source code is available, static analysis tools can identify unsafe width/height parameter handling in SceneCombiner.cpp. Monitor file system activity for suspicious model file uploads or temporary file creation during model processing.

Why prioritize this

Although the CVSS score is MEDIUM (5.3), this vulnerability warrants elevated attention in organizations where Assimp is exposed to untrusted model file sources or where local users have upload/execution capabilities. Public exploit availability and the simplicity of triggering heap overflow via file parameters make this a practical concern for engineering teams and content creation workflows. Prioritize patching if Assimp is integrated into customer-facing applications, design tools, or any service processing user-supplied 3D assets.

Risk score, explained

The CVSS v3.1 base score of 5.3 reflects local attack vector (AV:L), low privilege requirement (PR:L), no user interaction (UI:N), and impact on confidentiality, integrity, and availability (C:L/I:L/A:L). The score appropriately captures the bounded nature of local-only exploitation while acknowledging the potential for code execution and privilege escalation. Context-specific factors—such as whether the application processes untrusted files or runs in multi-tenant environments—may justify higher risk in your environment.

Frequently asked questions