CVE-2026-21308 is classified as an out-of-bounds read vulnerability (CWE-125) affecting Adobe Substance3D - Designer versions 15.0.3 and earlier. The vulnerability arises when the software improperly handles memory boundaries while processing input files, allowing an attacker to read memory locations beyond the intended buffer. This can lead to the exposure of sensitive information residing in adjacent memory areas. The attack vector requires a victim to open a specially crafted malicious file, making user interaction mandatory for exploitation. The vulnerability does not allow privilege escalation, code execution, or denial of service but compromises confidentiality by leaking memory contents. The CVSS v3.1 base score is 5.5, reflecting medium severity with the vector AV:L (local access), AC:L (low complexity), PR:N (no privileges required), UI:R (user interaction required), S:U (unchanged scope), C:H (high confidentiality impact), I:N (no integrity impact), and A:N (no availability impact). No patches or exploit code are currently publicly available, but the risk remains for targeted attacks against users who open malicious files. This vulnerability primarily affects creative professionals and organizations relying on Adobe Substance3D - Designer for 3D content creation and design workflows.

For European organizations, the primary impact of CVE-2026-21308 is the potential leakage of sensitive information from memory when users open malicious files in Adobe Substance3D - Designer. This could include intellectual property, design assets, or other confidential data processed by the software. While the vulnerability does not enable system takeover or data modification, the confidentiality breach could have significant consequences for companies in sectors such as media, entertainment, manufacturing, and product design. Exposure of proprietary design data could lead to competitive disadvantages or intellectual property theft. Additionally, the requirement for user interaction means phishing or social engineering could be used to deliver malicious files, increasing risk in environments with less stringent user training or file handling policies. The absence of known exploits reduces immediate threat but does not eliminate the risk of future targeted attacks. Organizations with remote or hybrid work models may face increased exposure if users handle files from untrusted sources.

To mitigate CVE-2026-21308, European organizations should: 1) Immediately update Adobe Substance3D - Designer to the latest version once Adobe releases a patch addressing this vulnerability. 2) Until a patch is available, implement strict file handling policies that restrict opening files from untrusted or unknown sources, especially email attachments or downloads. 3) Educate users about the risks of opening unsolicited or suspicious files and train them to recognize phishing attempts that may deliver malicious content. 4) Employ endpoint security solutions capable of detecting and blocking malicious files or anomalous application behavior related to Adobe Substance3D. 5) Use network segmentation to limit exposure of critical design workstations and monitor for unusual file access or data exfiltration attempts. 6) Regularly audit and monitor logs for signs of exploitation attempts or memory disclosure activities. 7) Coordinate with Adobe support channels to receive timely updates and advisories regarding this vulnerability.