CVE-2020-28602 is a medium-severity vulnerability affecting the CGAL Project's libcgal library, specifically version 5.1.1. The vulnerability arises from improper validation of array indices (CWE-129) within the Nef polygon-parsing functionality. The core issue is located in the PM_io_parser<PMDEC>::read_vertex() function in the Nef_2/PM_io_parser.h file, where an out-of-bounds (OOB) read occurs on the Halfedge_of[] array. This improper bounds checking allows a specially crafted malformed input file to trigger an out-of-bounds read and type confusion. Type confusion can lead to arbitrary code execution by causing the program to interpret data as a different type than intended. An attacker can exploit this vulnerability by supplying malicious input files to applications that utilize the vulnerable libcgal 5.1.1 library for polygon parsing. The vulnerability does not require authentication or user interaction beyond processing the malicious file. Although no known exploits are currently reported in the wild, the potential for remote code execution makes this a significant risk in environments where libcgal is used to process untrusted polygon data. The vulnerability affects the confidentiality, integrity, and availability of affected systems, as arbitrary code execution could lead to data theft, system compromise, or denial of service. The lack of a patch link suggests that remediation may require updating to a newer, fixed version of the CGAL library or applying vendor-specific mitigations.

For European organizations, the impact of this vulnerability depends largely on the use of CGAL libcgal 5.1.1 within their software stacks. CGAL is widely used in computational geometry, CAD, GIS, and scientific research applications. Organizations in sectors such as manufacturing, aerospace, automotive, and geospatial analysis in Europe may be at risk if they use vulnerable versions of libcgal to process polygon data, especially from untrusted sources. Exploitation could lead to unauthorized code execution, resulting in data breaches, intellectual property theft, or disruption of critical design and analysis workflows. Given the potential for remote code execution without user interaction, attackers could leverage this vulnerability to gain persistent access or move laterally within networks. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits post-disclosure. The impact is heightened in environments where CGAL is integrated into web services or automated pipelines that ingest external polygon data, increasing exposure to malicious inputs.

1. Upgrade to the latest version of the CGAL library where this vulnerability has been addressed. If an official patch is not yet available, monitor CGAL project communications for updates. 2. Implement strict input validation and sanitization on all polygon data before processing, especially if sourced externally. 3. Employ sandboxing or containerization to isolate applications using libcgal, limiting the impact of potential exploitation. 4. Restrict file input sources to trusted origins and implement file integrity checks to detect tampering. 5. Conduct code audits and static analysis on applications integrating libcgal to identify and remediate unsafe handling of polygon data. 6. Monitor logs and network traffic for anomalous behavior that could indicate exploitation attempts. 7. Where feasible, disable or limit the use of the Nef polygon-parsing functionality if it is not essential to reduce the attack surface.