CVE-2026-105716 in Office Access
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 flaw is typically triggered by processing specially crafted files or input that exceed expected boundaries during parsing operations. The attacker leverages this overflow to overwrite adjacent memory structures, which can lead to arbitrary code execution with the privileges of the current user. Because the vulnerability allows for remote exploitation over a network, it represents a significant threat vector where an adversary does not need physical access or local authentication to initiate the attack sequence.
From a technical perspective, heap-based buffer overflows are particularly dangerous because they allow attackers to manipulate memory allocation metadata and function pointers stored in adjacent heap chunks. By carefully crafting the input data, an attacker can control the flow of execution after the overflow occurs. This often involves redirecting program counter registers or invoking specific library functions that facilitate payload delivery. The ability to execute code remotely implies that the vulnerability likely resides in a component responsible for handling network requests or processing external file formats, such as database files (.accdb or .mdb) received via email attachments, shared drives, or web downloads. This aligns with common attack patterns where malicious documents are distributed through social engineering tactics to exploit trust relationships within an organization's infrastructure.
The operational impact of this vulnerability is severe, potentially leading to a complete compromise of the affected system. Once code execution is achieved, an attacker can install malware, steal sensitive data stored in Access databases, create new user accounts with administrative privileges, or use the compromised machine as a pivot point for further lateral movement within the network. This significantly expands the attack surface and undermines the confidentiality, integrity, and availability of organizational assets. The risk is compounded by the fact that Microsoft Office applications are ubiquitous in enterprise environments, making this vulnerability applicable to a vast number of potential targets across various industries.
To mitigate these risks, organizations must ensure that all systems running affected versions of Microsoft Office Access have received the latest security updates provided by Microsoft. These patches address the underlying memory handling errors and enforce stricter input validation mechanisms. Additionally, implementing application control policies can prevent unauthorized or untrusted applications from executing on endpoints. Network segmentation should be employed to limit the ability of attackers to propagate exploits across different network zones. Users must also be educated on recognizing suspicious email attachments and avoiding opening files from unknown sources. Regular vulnerability scanning and penetration testing can help identify instances where patches have not been applied, allowing for proactive remediation before exploitation occurs.
This vulnerability is categorized under CWE-122, which denotes a heap-based buffer overflow, highlighting the specific nature of the memory corruption involved. In terms of tactical classification within the MITRE ATT&CK framework, this scenario aligns with techniques related to initial access and execution, such as T1566.001 (Phishing: Spearphishing Attachment) for delivery and T1203 (Exploitation for Client Execution) for the exploitation phase. Understanding these classifications helps security teams map defensive controls more effectively against known adversary behaviors. Continuous monitoring of endpoint behavior for anomalous memory access patterns can also aid in detecting attempts to exploit this flaw, providing an additional layer of defense beyond patch management alone.