CVE-2026-108442 in Office
Summary
by MITRE • 10/16/2026
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/16/2026
The vulnerability described constitutes a critical security flaw within the document processing engine of Microsoft Office Word, specifically involving improper memory management during object lifecycle operations. This class of defect is technically categorized as a use-after-free error, which corresponds directly with Common Weakness Enumeration identifier CWE-416. In this scenario, an attacker can exploit the vulnerability by crafting a malicious file or manipulating network traffic that triggers the application to access and execute code from memory locations that have already been deallocated. The root cause typically stems from a logic error where pointers are not properly nullified after memory release, allowing stale references to remain valid in certain execution paths until they point to newly allocated data with attacker-controlled content.
From an operational perspective, the impact of this vulnerability is severe due to its potential for remote code execution over a network without requiring user interaction beyond opening or rendering the malicious document. When the vulnerable component processes specially crafted input, it may interpret freed memory as executable instructions or valid object structures controlled by the adversary. This allows the attacker to inject arbitrary shellcode into the process space of Microsoft Word, leading to full system compromise on the affected host. The ability to execute code remotely makes this a high-priority threat vector for phishing campaigns and targeted attacks where initial access is gained through social engineering tactics involving malicious documents distributed via email or file sharing services.
This vulnerability aligns with several techniques observed in advanced persistent threats as documented by the MITRE ATT&CK framework. Specifically, it facilitates Initial Access through spearphishing attachment mechanisms and enables Execution of arbitrary code on target systems. The exploitation path often involves bypassing standard security controls because the malicious payload is embedded within a trusted application binary or library loaded into memory during normal document rendering processes. Defenders should recognize that such vulnerabilities are frequently leveraged in zero-day campaigns where no patch exists, making proactive monitoring and behavioral analysis crucial for detection before an exploit succeeds.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is the timely application of security updates provided by Microsoft to address the specific memory handling flaws within Word components. Organizations should enforce strict policies regarding macro execution and disable unnecessary features such as ActiveX controls or external content loading that may expand the attack surface. Additionally, implementing application whitelisting can prevent unauthorized code from executing even if an exploit succeeds in gaining initial foothold. Network segmentation and endpoint detection and response solutions are also essential to limit lateral movement should a host become compromised through this vector. Regular vulnerability scanning and penetration testing focused on document processing applications will help identify similar weaknesses before they can be exploited by malicious actors seeking network-wide access.