CVE-2026-21307
Published: 13 January 2026
Summary
CVE-2026-21307 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Adobe Substance 3D Designer. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Client Execution (T1203); ranked at the 7.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-21307 is an out-of-bounds write vulnerability (CWE-787) affecting Adobe Substance3D Designer versions 15.0.3 and earlier. The flaw can lead to arbitrary code execution in the context of the current user when processing malicious input.
Exploitation requires local access (AV:L) with low complexity (AC:L), no privileges (PR:N), and user interaction (UI:R) in the form of opening a malicious file. A successful attack grants high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H) within the user's scope (S:U), as reflected in its CVSS v3.1 base score of 7.8.
Adobe's security bulletin APSB26-13 at https://helpx.adobe.com/security/products/substance3d_designer/apsb26-13.html provides further details on mitigation and available patches.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2031
Vulnerability details
Substance3D - Designer versions 15.0.3 and earlier are affected by an out-of-bounds write vulnerability that could result in arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must…
more
open a malicious file.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Out-of-bounds write enables client-side RCE via crafted file (T1203); requires user to open malicious file (T1204.002).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requires timely identification, testing, and installation of patches for known flaws like this out-of-bounds write vulnerability in Substance3D Designer.
Implements memory protections such as DEP and stack canaries that hinder arbitrary code execution from out-of-bounds writes.
Deploys malicious code protection to scan and block malicious files exploiting the vulnerability before user interaction.