CVE-2026-21303 is an out-of-bounds read vulnerability (CWE-125) identified in Adobe Substance3D - Modeler, a 3D modeling software widely used in digital content creation. The flaw exists in versions 1.22.4 and earlier, where the software improperly handles certain input data, leading to reading memory beyond the intended buffer boundaries. This memory exposure can leak sensitive information stored in the process memory space, potentially including user data or application secrets. Exploitation requires an attacker to craft a malicious file that, when opened by a victim using the vulnerable software, triggers the out-of-bounds read. The vulnerability does not allow for privilege escalation, code execution, or denial of service, but it compromises confidentiality. The CVSS v3.1 base score is 5.5, reflecting a local attack vector (AV:L), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The impact is limited to confidentiality (C:H), with no integrity or availability impact. No public exploits or patches are currently available, but the issue is officially published and tracked by Adobe. This vulnerability highlights the risk of handling untrusted 3D model files in creative workflows and the importance of secure file parsing.

For European organizations, particularly those in media, design, gaming, and digital content creation sectors using Adobe Substance3D - Modeler, this vulnerability poses a risk of sensitive information leakage. Confidential data such as project files, proprietary models, or user credentials stored in memory could be exposed if a malicious file is opened. While the vulnerability does not allow system compromise or disruption, the confidentiality breach could lead to intellectual property theft or leakage of sensitive business information. The requirement for user interaction reduces the likelihood of widespread automated exploitation but does not eliminate targeted attacks, especially in collaborative environments where files are shared. Organizations with remote or hybrid workforces may face increased risk if users open untrusted files received via email or file sharing. The absence of known exploits in the wild currently limits immediate risk, but the medium severity rating warrants proactive mitigation to prevent future exploitation.

European organizations should implement specific measures beyond generic advice: 1) Educate users, especially designers and content creators, on the risks of opening files from untrusted or unknown sources. 2) Enforce strict file validation and sandboxing policies for 3D model files before opening them in Substance3D - Modeler. 3) Monitor and restrict file sharing channels to reduce the risk of malicious files entering the environment. 4) Use endpoint detection and response (EDR) tools to monitor for suspicious application behavior related to Substance3D - Modeler. 5) Maintain an inventory of software versions and prioritize upgrading to patched versions once Adobe releases a fix. 6) Consider network segmentation to isolate systems used for 3D modeling from critical infrastructure. 7) Apply principle of least privilege to limit user permissions on workstations running the software. 8) Regularly review Adobe security advisories and subscribe to vulnerability notifications to stay informed of updates or patches.