CVE-2020-28599 in Openscad
Summary
by MITRE • 02/24/2021
A stack-based buffer overflow vulnerability exists in the import_stl.cc:import_stl() functionality of Openscad openscad-2020.12-RC2. A specially crafted STL file can lead to code execution. An attacker can provide a malicious file to trigger this vulnerability.
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Analysis
by VulDB Data Team • 06/15/2026
The vulnerability under examination represents a critical stack-based buffer overflow within the import_stl.cc module of OpenSCAD version 2020.12-RC2, specifically within the import_stl() function. This flaw constitutes a serious security weakness that can be exploited to achieve arbitrary code execution through the manipulation of STL file inputs. The vulnerability stems from inadequate input validation and bounds checking during the processing of three-dimensional model files, creating an exploitable condition where attacker-controlled data can overwrite adjacent memory locations on the stack. The affected software processes STL files for import purposes, making this vulnerability particularly dangerous as it can be triggered through normal file processing operations without requiring special privileges or complex attack vectors.
The technical implementation of this vulnerability manifests when the import_stl() function fails to properly validate the size of incoming data from STL files before copying it into fixed-size stack buffers. This classic buffer overflow scenario occurs because the software does not perform adequate bounds checking on the size of vertex data or other structural elements within the STL file format. When an attacker crafts a malicious STL file containing oversized data structures, the function attempts to copy this data into insufficiently sized memory buffers, causing stack memory corruption. The overflow can overwrite return addresses, function pointers, and other critical stack data, potentially allowing an attacker to redirect program execution flow to malicious code. This type of vulnerability is classified as CWE-121 Stack-based Buffer Overflow, which falls under the broader category of memory safety issues that have been consistently identified as high-risk threats in software security assessments.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a pathway to compromise systems running affected versions of OpenSCAD. Since STL files are commonly used in 3D modeling workflows and can be easily shared through various channels including email attachments, cloud storage, and collaborative platforms, the attack surface is extensive. An attacker could deliver a malicious STL file through social engineering or by compromising legitimate file repositories, leading to automatic code execution when users open these files within the vulnerable software. The exploitability of this condition is heightened by the fact that OpenSCAD is widely used in both professional and educational environments, making it a potentially attractive target for attackers seeking to compromise user systems. The vulnerability can be triggered without user interaction beyond opening the file, making it particularly dangerous in automated or unattended environments where file processing occurs automatically.
Mitigation strategies for this vulnerability should focus on immediate software updates and defensive programming practices. The most effective immediate solution involves upgrading to a patched version of OpenSCAD that addresses the buffer overflow condition through proper input validation and bounds checking mechanisms. Organizations should implement comprehensive patch management procedures to ensure all instances of the vulnerable software are updated promptly. Additionally, defensive measures including input sanitization, memory protection features such as stack canaries, and address space layout randomization should be considered as part of a broader security posture. The vulnerability demonstrates the importance of adhering to secure coding practices and following established security guidelines such as those outlined in the CWE top 25 most dangerous software weaknesses and the MITRE ATT&CK framework for understanding how such vulnerabilities can be leveraged in real-world attacks. Regular security assessments and code reviews focusing on memory safety issues should be implemented to prevent similar vulnerabilities from emerging in future releases.