Assimp CVE-2026-19970

Exploitation requires that the target application embeds Assimp and exposes MDL7 (3D Game Studio MDL version 7) format parsing to attacker-influenced file input - applications that only process other formats (OBJ, FBX, glTF, DAE, etc.) are not affected by this specific code path. User interaction is required per CVSS 4.0 UI:P: a user or automated process must trigger the parsing of the malicious file. No authentication or elevated privileges are required by Assimp itself (PR:N), but the attack is indirect - the attacker must first deliver the crafted file to a context where it will be parsed. The specific limiting factors are: the application must support MDL7 import, and the file must reach the AddBonesToNodeGraph_3DGS_MDL7 function, which handles the bone-to-node-graph step of MDL7 parsing. Applications that only use Assimp for non-MDL formats are not exposed.

The CVSS 4.0 score of 5.3 with E:P reflects medium severity modulated by the user-interaction requirement (UI:P) - a victim application must parse an attacker-supplied MDL file - and the low impact ratings across confidentiality, integrity, and availability. However, the CVSS impact ratings merit scrutiny: CWE-122 heap overflows are a class commonly associated with arbitrary code execution, and the low VC/VI/VA ratings may understate true impact if the overflow is reliably controllable. The publicly available POC zip on GitHub (E:P in the CVSS 4.0 vector) is the most significant risk amplifier here - exploitation complexity drops substantially once working exploit code circulates. This vulnerability is not listed in CISA KEV, so widespread active exploitation is not confirmed; the absence of a vendor response to the disclosure, however, means no fix timeline exists. For organizations running Assimp in content pipelines or tools that accept third-party 3D assets - even a mid-sized studio or municipal digital asset management team - the combination of no patch, public POC, and low attack complexity makes this a credible near-term threat worth prioritizing for compensating controls.

An attacker crafts a malicious MDL7 3D model file containing an oversized or malformed bones_num value, then delivers it to a target via a file-sharing link, email attachment, or upload to a platform that processes 3D assets using Assimp. When the application parses the file, AddBonesToNodeGraph_3DGS_MDL7 writes past the end of a heap-allocated buffer, corrupting adjacent memory. A publicly available POC archive confirms reproducibility; a motivated attacker with heap exploitation experience could potentially develop this into a reliable code execution primitive.