# CVE-2026-21343: Adobe Substance3D Stager out-of-bounds read in file parsing

Source: https://junglewise.ai/threats/cve-2026-21343-adobe-substance3d-stager-out-of-bounds-read-in-file-parsing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-10. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-21343 · Severity: high · CVSS 7.8 · Published 2026-02-10

Substance3D Stager is a 3D asset preparation tool used by designers and creative professionals. A flaw in how it processes crafted files allows reading past the end of allocated memory, potentially enabling attackers to execute arbitrary code on a user's system when they open a malicious file. The attack requires user interaction but poses a significant risk to creative workflows and systems handling sensitive design assets.

Technologies: [Adobe Substance 3d Stager](https://junglewise.ai/threats/technologies/substance-3d-stager), [Adobe Substance3D Stager](https://junglewise.ai/threats/technologies/substance3d-stager), [Apple macOS](https://junglewise.ai/threats/technologies/macos), [Microsoft Windows](https://junglewise.ai/threats/technologies/windows). Vendors: [Adobe](https://junglewise.ai/threats/vendors/adobe), [Apple](https://junglewise.ai/threats/vendors/apple), [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-21343 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-21343 being exploited in the wild.

**How severe is CVE-2026-21343?** High severity, with a CVSS score of 7.8, published 10 February 2026.

**Which products and versions are affected?** Adobe Substance3D Stager 3.1.6 and earlier.

**Is there a fix for CVE-2026-21343?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-21343 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-21343?** Check whether you run Adobe Substance 3d Stager, Adobe Substance3D Stager, Apple macOS or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read (CWE-125) in Substance3D Stager's file parsing functionality that permits reading past the end of an allocated memory structure. The root cause lies in insufficient bounds checking when processing crafted input files. The attack vector is local with user interaction required—a victim must open a malicious file. Successful exploitation allows code execution in the context of the current user. The vulnerability affects versions 3.1.6 and earlier; patched versions should be available from Adobe.

## Affected products

- Adobe Substance3D Stager 3.1.6 and earlier

## Timeline

- 2026-02-10: disclosed

## References

- [https://helpx.adobe.com/security/products/substance3d_stager/apsb26-20.html](https://helpx.adobe.com/security/products/substance3d_stager/apsb26-20.html)

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