CVE-2026-50301
Summary
by MITRE • 07/14/2026
Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 07/14/2026
A heap-based buffer overflow vulnerability exists within Microsoft Office applications that enables unauthorized attackers to execute arbitrary code on affected systems. This critical security flaw resides in the memory management mechanisms of Microsoft Office software, specifically within the heap allocation and deallocation processes. The vulnerability occurs when the application fails to properly validate input data before copying it into heap-allocated memory buffers, allowing an attacker to overwrite adjacent memory locations with malicious payload data. Such buffer overflow conditions are classified under CWE-121 heap-based buffer overflow which represents one of the most prevalent and dangerous classes of memory corruption vulnerabilities in software applications.
The technical exploitation of this vulnerability requires an attacker to craft specially formatted Office documents that trigger the flawed memory handling logic during document processing. When a user opens the malicious file, the Office application attempts to parse the malformed input data and store it in heap memory without adequate bounds checking. This allows the attacker to overwrite critical memory structures including return addresses, function pointers, or other control data that govern program execution flow. The vulnerability is particularly concerning because it enables local code execution, meaning an attacker who can convince a user to open a malicious document can gain complete control over the victim's system. Attackers can leverage this primitive to install backdoors, steal sensitive information, or escalate privileges to SYSTEM level access on the compromised machine.
The operational impact of this vulnerability extends beyond simple remote code execution as it represents a significant threat vector for advanced persistent threats and zero-day attacks. Organizations running vulnerable versions of Microsoft Office are at risk of targeted attacks where adversaries craft specific Office documents designed to exploit this heap overflow condition. The attack surface is broad since Office applications are widely deployed across enterprise environments, making it an attractive target for cybercriminals seeking to establish persistent footholds within networks. According to ATT&CK framework, this vulnerability maps to T1059 command and control communication and T1068 local privilege escalation techniques that attackers frequently employ after initial compromise through document-based attacks.
Mitigation strategies must address both immediate defensive measures and long-term security improvements for affected systems. Microsoft has released security updates and patches that correct the heap overflow conditions by implementing proper input validation, bounds checking, and memory management controls within Office applications. Organizations should prioritize immediate deployment of these security patches across all vulnerable systems while maintaining comprehensive monitoring for potential exploitation attempts. Additional defensive measures include implementing application whitelisting policies that restrict execution of untrusted Office documents, enabling exploit protection features such as data execution prevention, and deploying intrusion detection systems to monitor for suspicious network traffic patterns associated with exploitation activities. The vulnerability also highlights the importance of user education and awareness programs to prevent social engineering attacks that rely on tricking users into opening malicious Office documents, thereby reducing the attack surface and overall risk exposure for enterprise environments.