CVE-2026-21339: 
Adobe Substance 3D Designer vulnerability analysis and mitigation

CVE-2026-21339 is an out-of-bounds read vulnerability (CWE-125) in Adobe Substance 3D Designer that could lead to sensitive memory disclosure. It affects Substance 3D Designer versions 15.1.0 and earlier (all versions prior to 15.1.2). Adobe disclosed and patched this vulnerability on February 10, 2026. It carries a CVSS v3.1 base score of 5.5 (Medium) (Adobe Advisory).

The vulnerability is classified as CWE-125 (Out-of-bounds Read), where the application reads data beyond the allocated memory buffer boundaries when processing a specially crafted file. Exploitation requires local access and user interaction — specifically, a victim must open a malicious file, triggering the out-of-bounds read condition. The attack vector is local with low attack complexity and no privileges required, meaning an attacker can craft a malicious file and socially engineer a target user into opening it (Adobe Advisory). No public proof-of-concept or detailed technical write-up is currently available.

Successful exploitation results in memory disclosure, allowing an attacker to read sensitive data from the application's memory space. The confidentiality impact is rated High, while integrity and availability are unaffected. The scope is limited to the local system running the vulnerable Substance 3D Designer application, with no evidence of lateral movement potential beyond the exposed in-memory data (Adobe Advisory).

Adobe has released a patch in Substance 3D Designer version 15.1.2, which resolves this vulnerability. Users should update to version 15.1.2 or later as the primary remediation step. As an interim measure, users should avoid opening Substance 3D Designer files from untrusted or unknown sources until the patch is applied (Adobe Advisory).

The Center for Internet Security (CIS) published an advisory noting multiple vulnerabilities in Adobe products patched in February 2026, including CVE-2026-21339, as part of Adobe's broader February 2026 patch release (CIS Advisory). No significant independent researcher commentary or notable social media discussion has been observed for this specific CVE, consistent with its medium severity rating and lack of active exploitation.