CVE-2026-102857 in Office
Summary
by MITRE • 10/13/2026
Heap-based buffer overflow in Microsoft Office Visio allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Office Visio application, specifically manifesting as a heap-based buffer overflow. This type of memory corruption error occurs when a program writes data beyond the allocated boundaries of a buffer located in the computer's random access memory, known as the heap. In the context of Visio, this defect is triggered by processing specially crafted files or network traffic that exploits improper bounds checking during the parsing of diagrammatic data structures. The presence of such an overflow allows for arbitrary code execution with elevated privileges, potentially granting an attacker full control over the affected system. This capability transforms a simple rendering error into a severe remote code execution vector, enabling adversaries to install malware, exfiltrate sensitive information, or establish persistent access within corporate networks that rely heavily on Visio for technical documentation and network topology mapping.
From a technical perspective, heap-based buffer overflows are particularly dangerous because the heap is used for dynamic memory allocation during program runtime. When an attacker can control the data written to this region, they may overwrite adjacent memory structures such as function pointers or exception handling records. This manipulation allows the execution flow of the application to be redirected toward malicious shellcode injected by the attacker. The vulnerability likely stems from insufficient validation of input lengths or types when Visio processes complex vector graphics or embedded objects received via network protocols. Such flaws are often rooted in legacy code paths that have not been adequately hardened against modern exploitation techniques, where attackers utilize sophisticated payload construction to bypass memory protection mechanisms like Data Execution Prevention and Address Space Layout Randomization.
The operational impact of this vulnerability is severe due to its potential for remote exploitation over a network. An attacker does not necessarily need physical access or user interaction beyond the initial delivery mechanism, which could involve sending a malicious Visio file via email or hosting it on a compromised website that triggers automatic download and execution upon viewing in certain configurations. Once executed, the code runs with the security context of the logged-in user. If the user operates with administrative privileges, the attacker gains complete control over the system. This can lead to significant data breaches, lateral movement within an enterprise network, and disruption of critical business operations that depend on accurate technical diagrams and documentation managed through Visio. The ability to execute code remotely makes this a high-priority threat for organizations maintaining large repositories of engineering or IT infrastructure documents.
To mitigate the risks associated with this vulnerability, immediate patching is essential. Organizations should apply the latest security updates provided by Microsoft for their versions of Office Visio and the broader Office suite. These patches typically include fixes that enforce stricter memory management practices and improve input validation routines to prevent buffer overflows from occurring in the first place. In addition to software updates, administrators should implement application whitelisting policies to restrict the execution of untrusted binaries and configure network security appliances to inspect traffic for known exploit signatures related to Visio file formats. User awareness training is also critical; employees should be educated on the risks of opening files from unknown sources or accessing untrusted web content that may trigger automatic rendering of malicious documents. Finally, deploying endpoint detection and response solutions can help identify anomalous behavior indicative of exploitation attempts, such as unusual memory allocation patterns or unexpected process spawns following Visio activity, allowing for rapid incident containment and remediation efforts aligned with industry standards like the Common Weakness Enumeration framework which categorizes this flaw under CWE-122.