CVE-2026-19967 in Assimp
Summary
by MITRE • 08/17/2026
A security flaw has been discovered in Open Asset Import Library Assimp 17c12da. Impacted is the function Assimp::Compression::decompressBlock of the file code/Common/Compression.cpp of the component File Parser. Performing a manipulation results in heap-based buffer overflow. The attack may be initiated remotely. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 08/23/2026
The Open Asset Import Library, commonly known as Assimp, is a widely adopted open-source library designed to facilitate the importation of various 3D model and animation file formats into applications such as game engines, computer-aided design software, and visualization tools. A critical security vulnerability has been identified within version 17c12da specifically affecting the decompression logic located in the code/Common/Compression.cpp file. The flaw resides in the Assimp::Compression::decompressBlock function, which is responsible for handling compressed data blocks during the parsing of supported asset files. This component operates as part of the broader File Parser subsystem, processing input streams that may contain zlib or other compression algorithms depending on the specific format being imported.
The technical nature of this vulnerability constitutes a heap-based buffer overflow, classified under CWE-122 in the Common Weakness Enumeration taxonomy. The root cause lies in an improper calculation or validation of memory allocation sizes relative to the actual data size contained within the compressed block. When the decompression routine processes a maliciously crafted file where the header information indicates a larger uncompressed size than what is actually available, or when internal state management fails to account for boundary conditions during expansion, the library attempts to write beyond the allocated heap memory region. This discrepancy allows an attacker to overwrite adjacent memory structures on the heap, potentially corrupting data pointers, function return addresses, or other critical control flow elements within the application process space.
Because Assimp is frequently integrated into applications that handle untrusted 3D assets from external sources, this vulnerability presents a significant remote attack vector. An adversary can construct a specially crafted 3D model file containing malformed compressed blocks designed to trigger the overflow condition upon import or parsing by the vulnerable software. The exploit has been publicly released, indicating that proof-of-concept code is available for testing and potentially weaponization. Successful exploitation could lead to arbitrary code execution with the privileges of the user running the application, denial of service through application crashes caused by memory corruption, or information disclosure if specific heap metadata can be leaked during the overflow process.
From a threat intelligence perspective, this vulnerability aligns with ATT&CK techniques related to initial access and execution via compromised files. Attackers may distribute malicious 3D assets through phishing campaigns, compromised repositories, or legitimate-looking software updates to trick users into opening infected models in vulnerable applications like Blender, Unity, Unreal Engine plugins, or custom visualization tools that rely on Assimp for asset loading. The lack of a timely response from the project maintainers despite early notification increases the risk window during which systems remain exposed without official patches.
Mitigation strategies must focus on immediate operational controls and long-term remediation steps. Organizations relying on this version of Assimp should consider implementing strict input validation at the application layer, ensuring that only trusted sources are allowed to trigger asset parsing routines if possible. Network-level filtering or sandboxing can also reduce exposure by preventing untrusted 3D files from reaching vulnerable systems until a patch is applied. Developers integrating Assimp into their products should evaluate upgrading to a patched version as soon as it becomes available from the official repository, verifying that the fix addresses the boundary checks in the decompression logic. Additionally, enabling heap protection mechanisms such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) can mitigate the likelihood of successful code execution by making memory layout unpredictable and preventing direct execution of injected shellcode from writable memory regions. Continuous monitoring for anomalous behavior during file parsing operations may also help detect attempted exploitation in real-time environments.