Adobe Substance 3D Stager: Out-of-bounds write allows code execution
Summary
Adobe Substance 3D Stager versions 3.1.8 and earlier contain an out-of-bounds write vulnerability (CWE-787). If a user opens a malicious file, an attacker can execute arbitrary code with the privileges of the current user. The attack requires no authentication but depends on user interaction, and the vulnerability is rated High (CVSS 7.8).
Affected
- Adobe Substance 3D Stager 3.1.8 and earlier (Windows and macOS)
- Start of the affected range: Unknown.
Fixed in
- Adobe Substance 3D Stager 3.1.9 or later
Workaround
- No vendor-documented workaround.
- Interim measure until the update is deployed (not from the vendor): open Stager project files only from trusted sources and warn users about unsolicited attachments.
Exploitation
- Adobe is not aware of any exploits in the wild for the issues in this update.
- No public proof of concept found. CISA KEV status not verified.
Our recommendation
- Update Adobe Substance 3D Stager to 3.1.9 or later via the Creative Cloud desktop app, or deploy it through the Admin Console in managed environments.
- Verify the installed version on each workstation, especially on design and media systems that handle third-party 3D files.
- Patch the whole product, because the same advisory (APSB26-170) addresses several related high and medium issues.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Adobe Security Bulletin APSB26-170 www.adobe.com
- Vulners: CVE-2026-103839 vulners.com
- OffSeq Radar: CVE-2026-103839 radar.offseq.com
- Mallory: related Stager advisory issues mallory.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 2 Nov 2026, 00:15.
Original description (NVD)
Substance3D - Stager is 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 open a malicious file.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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