CVE-2020-28604 is a medium-severity vulnerability affecting version 5.1.1 of the CGAL Project's libcgal library, specifically within the Nef polygon-parsing functionality. The root cause is an improper validation of array indices (CWE-129) in the PM_io_parser<PMDEC>::read_hedge() function located in Nef_2/PM_io_parser.h. This flaw allows an attacker to supply a specially crafted malformed input file that triggers an out-of-bounds (OOB) read and type confusion. The OOB read occurs when the function attempts to set a pointer to the next half-edge (e->set_next()) without properly validating the index, leading to memory corruption. This memory corruption can be leveraged to execute arbitrary code within the context of the vulnerable application. The vulnerability arises from insufficient bounds checking on array indices during polygon parsing, which is a critical step in processing geometric data. Although no public exploits are currently known in the wild, the vulnerability poses a risk to any software or systems that utilize libcgal 5.1.1 for geometric computations, especially those that parse untrusted or user-supplied polygon files. The lack of authentication or user interaction requirements means that if an attacker can supply a malicious file to the vulnerable parser, exploitation is feasible. The vulnerability affects confidentiality, integrity, and availability since arbitrary code execution can lead to data theft, manipulation, or denial of service. No official patches or updates are listed, indicating that users must monitor CGAL project releases for remediation or consider alternative mitigations.

For European organizations, the impact of this vulnerability depends on the extent to which libcgal 5.1.1 is integrated into their software stacks, particularly in industries relying on computational geometry such as CAD/CAM, GIS, robotics, and scientific research. Exploitation could allow attackers to execute arbitrary code, potentially leading to unauthorized access, data breaches, or disruption of critical services. Organizations processing untrusted polygon data files—such as those accepting user uploads or integrating third-party data—are at higher risk. The vulnerability could be leveraged in targeted attacks against intellectual property or critical infrastructure that uses CGAL for geometric computations. Given the medium severity and absence of known exploits, the immediate risk is moderate; however, the potential for escalation exists if exploit code becomes publicly available. The impact on availability could be significant if attackers cause crashes or denial of service. Confidentiality and integrity risks stem from arbitrary code execution capabilities. European organizations in sectors like manufacturing, aerospace, automotive, and geospatial services should be particularly vigilant.

1. Audit all software and systems to identify usage of libcgal 5.1.1, especially components that parse polygon files or geometric data. 2. Restrict or sanitize all inputs to the vulnerable polygon parsing functionality, ensuring only trusted or validated files are processed. 3. Implement strict input validation and sandboxing around components using libcgal to limit the impact of potential exploitation. 4. Monitor CGAL project repositories and security advisories for patches or updates addressing CVE-2020-28604 and apply them promptly. 5. If patching is not immediately possible, consider isolating or disabling the vulnerable parsing functionality where feasible. 6. Employ runtime protections such as Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), and control-flow integrity to mitigate exploitation impact. 7. Conduct code reviews and penetration testing focused on polygon parsing modules to detect similar vulnerabilities. 8. Educate developers and security teams about the risks of improper array index validation and secure coding practices in geometric libraries.