CVE-2026-105717 in 365 Apps for Enterprise
Summary
by MITRE • 10/14/2026
Heap-based buffer overflow in Microsoft Office Access 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 Access application, specifically manifesting as a heap-based buffer overflow condition. This type of memory corruption error occurs when a program writes more data to a dynamically allocated block of memory on the heap than it was intended to hold. In the context of Microsoft Office Access, this defect is triggered by processing specially crafted files or inputs that exceed expected boundaries for internal buffers used during file parsing or object manipulation. The root cause typically lies in insufficient validation of input lengths and types before copying data into fixed-size memory regions allocated on the heap. This lack of rigorous boundary checking allows an attacker to overwrite adjacent memory structures, potentially corrupting critical control data such as function return addresses or pointer values stored within the same allocation block.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-122, which defines heap-based buffer overflows where the overflow occurs in dynamically allocated memory rather than on the stack. The exploitation of such flaws often involves carefully crafted payloads designed to manipulate the program's execution flow. By controlling the content written beyond the buffer limit, an attacker can achieve arbitrary code execution with the privileges of the user running the application. This is particularly dangerous because Microsoft Office Access is frequently used in enterprise environments where users may have elevated permissions or access sensitive databases containing proprietary business logic and personal identifiable information. The ability to execute code remotely via a network connection significantly lowers the barrier for exploitation, allowing attackers to target vulnerable systems without requiring physical access or local user interaction beyond opening a malicious file sent over email or accessed through shared drives.
The operational impact of this vulnerability is severe, as it enables unauthorized remote code execution (RCE). An attacker who successfully exploits this flaw can install programs, view, change, or delete data, and create new accounts with full user rights on the affected system. This effectively compromises the confidentiality, integrity, and availability of the host machine and any connected network resources. In a corporate setting, such an incident could lead to significant financial loss, reputational damage, and regulatory non-compliance due to the exposure of sensitive data stored within Access databases. Furthermore, because Microsoft Office applications are ubiquitous in business workflows, this vulnerability presents a high-value target for automated scanning tools and advanced persistent threat actors seeking initial access points into internal networks.
To mitigate the risks associated with this heap-based buffer overflow, organizations must prioritize immediate patching by applying the latest security updates released by Microsoft for all versions of Microsoft Office Access that are still supported under the product lifecycle policy. It is crucial to verify that systems have received specific patches addressing CVE identifiers related to memory corruption in Office components. In addition to software updates, implementing strict email filtering rules can help prevent malicious files from reaching end-users' inboxes. Enabling Protected View for documents opened from potentially unsafe locations adds an additional layer of defense by isolating the document processing environment. Furthermore, restricting user privileges so that employees do not run Microsoft Office applications with administrative rights reduces the potential impact if exploitation occurs. Regular security awareness training should also be conducted to educate users on recognizing suspicious attachments and links, thereby reducing the likelihood of successful social engineering attacks that precede technical exploitation.