CVE-2026-103840 in Substance 3D Stager
Summary
by MITRE • 10/13/2026
Substance3D - Stager is affected by an out-of-bounds read vulnerability when parsing a crafted file, which could result in a read past the end of an allocated memory structure. An attacker could leverage this vulnerability to execute code in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
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Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability resides within Substance3D Stager, specifically affecting its file parsing mechanisms. This component is susceptible to an out-of-bounds read error when processing specially crafted input files. The core technical flaw involves the application failing to properly validate boundary conditions during the extraction or interpretation of data structures embedded in these malicious documents. Consequently, the software attempts to access memory locations that lie beyond the allocated buffer limits, leading to a read operation past the end of an assigned memory structure. This type of error is classically categorized under CWE-125, which defines out-of-bounds read vulnerabilities where a program reads data from outside the intended boundaries of a buffer or array.
The operational impact of this vulnerability extends beyond simple information disclosure due to the specific nature of how modern application environments handle memory and execution contexts. While an out-of-bounds read typically allows for the leakage of sensitive internal state, such as cryptographic keys or user credentials stored in adjacent memory regions, the description indicates that exploitation can lead to code execution within the context of the current user. This suggests that the vulnerability may be part of a more complex attack chain where the initial information leak facilitates further exploitation techniques, potentially involving heap spraying or other memory corruption primitives that allow an attacker to redirect control flow and execute arbitrary commands on the victim's system.
From a threat actor perspective, this vulnerability aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution. The requirement for user interaction is a critical factor in the risk assessment of this flaw. An adversary must successfully trick a target into opening or loading a malicious file that triggers the parsing routine within Substance3D Stager. This social engineering component means that automated remote exploitation without any user action is not feasible, thereby limiting the attack surface to targeted phishing campaigns or compromised content delivery networks where users are induced to download and open specific files.
Mitigation strategies for this vulnerability primarily focus on patch management and operational security awareness. Users should immediately update Substance3D Stager to the latest version provided by Adobe, as vendors typically release patches that include bounds checking improvements and stricter input validation logic to prevent out-of-bounds access. In environments where automatic updates are not feasible, administrators can implement application whitelisting policies to restrict the execution of untrusted binaries or disable file associations for Substance3D Stager with potentially dangerous file types until a patch is applied. Additionally, security awareness training should emphasize the risks associated with opening files from unknown sources, particularly those designed to exploit common creative software suites that are frequently targeted due to their widespread use in professional workflows.