CVE-2025-2592: Assimp Heap Buffer Overflow Vulnerability

CVE-2025-2592 Overview

A heap-based buffer overflow vulnerability has been identified in Open Asset Import Library (Assimp) version 5.4.3. This vulnerability exists within the CSMImporter::InternReadFile function located in the file code/AssetLib/CSM/CSMLoader.cpp. An attacker can exploit this flaw remotely by supplying a maliciously crafted CSM file, potentially leading to memory corruption and application instability.

Critical Impact

Successful exploitation of this heap-based buffer overflow could allow attackers to corrupt memory, crash applications using Assimp, or potentially achieve code execution in affected environments that process untrusted 3D model files.

Affected Products

• Open Asset Import Library (Assimp) version 5.4.3
• Applications and game engines integrating vulnerable Assimp versions
• 3D modeling pipelines processing CSM format files

Discovery Timeline

• 2025-03-21 - CVE-2025-2592 published to NVD
• 2025-07-17 - Last updated in NVD database

Technical Details for CVE-2025-2592

Vulnerability Analysis

This vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). The flaw resides in the CSM file loader component of Assimp, specifically within the CSMImporter::InternReadFile function. When parsing CSM (Character Studio Motion) files, the loader fails to properly validate input data boundaries before performing memory operations, resulting in a heap-based buffer overflow condition.

The vulnerability can be triggered remotely when an application using Assimp processes a maliciously crafted CSM file. Since Assimp is widely used in game engines, 3D modeling applications, and asset pipelines, this vulnerability has the potential to affect a broad range of software that processes untrusted 3D model files.

Root Cause

The root cause stems from insufficient bounds checking in the CSM file parsing logic. The CSMImporter::InternReadFile function does not adequately validate the size or structure of input data before allocating and writing to heap memory buffers. This allows an attacker to craft a CSM file with malformed data that triggers writes beyond the allocated buffer boundaries.

Attack Vector

The attack is network-accessible, meaning an attacker can deliver a malicious CSM file through various channels including email attachments, web downloads, or shared file repositories. User interaction is required as the victim must open or process the malicious file using an application that incorporates the vulnerable Assimp library.

The exploitation flow involves:

1. Attacker creates a specially crafted CSM file with malformed data
2. Victim's application loads the malicious file using Assimp
3. The CSMImporter::InternReadFile function processes the file
4. Insufficient bounds validation allows heap buffer overflow
5. Memory corruption occurs, potentially leading to crashes or code execution

Detection Methods for CVE-2025-2592

Indicators of Compromise

• Unexpected application crashes when processing CSM format 3D model files
• Memory access violations or segmentation faults in applications using Assimp
• Unusual heap memory patterns or corruption detected by memory sanitizers
• Crash dumps indicating faults within CSMLoader.cpp or related Assimp modules

Detection Strategies

• Implement file integrity monitoring for CSM files processed by your applications
• Deploy runtime memory protection tools such as AddressSanitizer to detect heap corruption
• Monitor application logs for crashes or exceptions originating from Assimp library functions
• Utilize endpoint detection and response (EDR) solutions to identify abnormal process behavior following file operations

Monitoring Recommendations

• Enable crash reporting and centralized logging for applications utilizing Assimp
• Monitor for suspicious CSM file activity, particularly files from untrusted sources
• Implement network traffic analysis to detect delivery of potentially malicious 3D model files
• Configure application whitelisting to restrict execution of untrusted content

How to Mitigate CVE-2025-2592

Immediate Actions Required

• Identify all applications and systems using Assimp version 5.4.3 or earlier
• Apply the security patch identified by commit 2690e354da0c681db000cfd892a55226788f2743
• Restrict processing of CSM files from untrusted sources until patching is complete
• Implement input validation for 3D model files at application boundaries

Patch Information

The Assimp development team has addressed this vulnerability through a specific commit. The patch is identified by commit hash 2690e354da0c681db000cfd892a55226788f2743. Organizations should update their Assimp installations by applying this patch or upgrading to a version that includes this fix.

For detailed patch information, refer to the GitHub Commit Update and the associated GitHub Pull Request.

Workarounds

• Disable CSM file format support in Assimp if not required by your application
• Implement file type validation to reject CSM files from untrusted sources
• Use sandboxing or process isolation when processing untrusted 3D model files
• Deploy memory protection mechanisms such as ASLR and DEP at the operating system level

# Example: Rebuild Assimp with the security patch applied
git clone https://github.com/assimp/assimp.git
cd assimp
git checkout 2690e354da0c681db000cfd892a55226788f2743
mkdir build && cd build
cmake ..
make -j$(nproc)
sudo make install