CVE-2026-10201: Assimp FBX Divide-by-Zero Denial of Service

Technical summary

The vulnerability stems from insufficient input validation in Assimp's FBX exporter when processing UV channel data. The FBXExporter::WriteObjects function fails to validate a numeric value before using it as a divisor, allowing a zero value to reach a division operation. This triggers an unhandled divide-by-zero exception (CWE-369), resulting in process termination. The flaw is compounded by inadequate error handling that does not gracefully catch or prevent the exception (CWE-404). Affected versions include Assimp up to and including 6.0.4. The vulnerability requires local code execution context and user-level privileges; it cannot be exploited remotely or without authentication.

Business impact

For organizations embedding Assimp in desktop or server-based 3D modeling tools, media conversion pipelines, or game asset importers, this vulnerability introduces a denial-of-service vector. An employee or operator who opens a malicious FBX file can crash the application, disrupting workflows and causing data loss if unsaved work is in progress. In automated batch-processing environments (e.g., asset pipelines), a poisoned file can halt processing queues. The risk is typically low for organizations where file sources are controlled and validated, but higher for those accepting 3D models from untrusted or external sources.

Affected systems

Assimp versions up to 6.0.4 are vulnerable. Any application or service that links against vulnerable Assimp releases and exposes FBX import/export functionality is at risk. Common affected use cases include: 3D modeling and animation tools, game engines with built-in asset import, media conversion utilities, architectural visualization software, and automated asset pipelines. Web services that process FBX files server-side are theoretically at lower risk due to the local-only requirement, but internal tools and desktop applications are directly exposed.

Exploitability

The attack is straightforward: a specially crafted FBX file with a zero value in a specific UV channel field is supplied to an application using vulnerable Assimp. No special privileges beyond local user access are required; execution occurs in-process when the file is opened or exported. Proof-of-concept code has been publicly disclosed, lowering the barrier for potential attackers. However, exploitation is limited to local scenarios—remote code execution is not possible, and the attacker must have the ability to place a file where the target application will process it. In many enterprise environments with restricted file sources, this constraint significantly reduces practical risk.

Remediation

Upgrade Assimp to a patched version beyond 6.0.4. Verify the exact version number and availability date against the official Assimp project repository and release notes. Implement input validation and sanitization for FBX files before processing, particularly in high-risk scenarios. Consider restricting FBX import to known-good sources and scanning files with static analysis tools when possible. For organizations unable to patch immediately, monitor application logs for unexpected crashes during FBX operations and restrict user access to 3D import features where feasible.

Patch guidance

Check the official Assimp GitHub repository and release notes to identify the first patched version after 6.0.4. Once confirmed, test the upgrade in a non-production environment with your application stack before deployment. If you maintain custom builds of Assimp, apply the corresponding fix to the FBXExporter.cpp file—specifically, add null checks and validation for the divisor before the division operation in FBXExporter::WriteObjects. Verify that your patched build resolves the divide-by-zero condition and does not introduce regressions. In container or virtualized environments, update base images and rebuild deployments to include the patched library version.

Detection guidance

Monitor for application crashes with stack traces mentioning FBXExporter.cpp or divide-by-zero exceptions during FBX file processing. Log file access and import operations in 3D tools, flagging unusual or unexpected .fbx files in processing pipelines. Use static analysis on third-party FBX files to detect anomalies in UV channel structures. Application performance monitoring (APM) tools can detect sudden terminations of asset import processes. If feasible, run Assimp-dependent services in sandboxed or containerized environments to limit the blast radius of crashes and simplify recovery.

Why prioritize this

Although CVE-2026-10201 carries a low CVSS score (3.3) due to its local-only attack vector and availability-only impact, the public disclosure of proof-of-concept code and the commonality of Assimp in 3D asset pipelines warrant timely attention. Prioritize patching for organizations with open file imports, collaborative asset workflows, or user-facing 3D tools. For environments with closed, validated file sources, the risk is minimal but not zero; schedule patching in routine maintenance windows. The vulnerability is not emergency-tier but should not be deferred indefinitely.

Risk score, explained

The CVSS 3.1 score of 3.3 (LOW) reflects the attack vector (Local only, AV:L), attack complexity (Low, AC:L), privilege requirement (Low, PR:L), user interaction (None, UI:N), scope (Unchanged, S:U), and impact (Availability only, A:L with Confidentiality and Integrity unaffected). This scoring is appropriate: the flaw causes denial of service via crash, not data theft or corruption. The local-only requirement and need for user-level access significantly constrain the threat landscape compared to network-exploitable vulnerabilities. However, the low bar to exploitation and public PoC availability mean tactical risk should be assessed in context of your specific deployment model and file-handling practices.

Frequently asked questions