Open Asset Import Library Assimp Out-of-Bounds Write Vulnerability in CSM File Handler

A critical out-of-bounds write vulnerability has been identified in Open Asset Import Library (Assimp) version 5.4.3. The issue arises in the CSM File Handler component, specifically within the 'Assimp::CSMImporter::InternReadFile' function, located in 'code/AssetLib/CSM/CSMLoader.cpp'. This vulnerability can be exploited remotely, potentially leading to arbitrary code execution, if a victim is tricked into processing a malformed CSM file with Assimp.

Impact

Exploitation of this vulnerability causes a segmentation fault due to a write operation to a null pointer, which can be leveraged to execute arbitrary code.

Reproduction

The vulnerability can be reproduced by building Assimp with address sanitizer and fuzzer support. After compiling the library, the fuzzer can be run with a crafted input that triggers the out-of-bounds write by manipulating the CSM importer's file reading function.