CVE-2021-1716 in Word
Summary
by MITRE • 01/13/2021
Microsoft Word Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-1715.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/04/2025
Microsoft Word remote code execution vulnerability CVE-2021-1716 represents a critical security flaw in Microsoft Office Word applications that allows attackers to execute arbitrary code on vulnerable systems. This vulnerability specifically affects Microsoft Word versions including Word 2016, Word 2019, Word 2021, and Office 2021, making it a widespread concern across enterprise environments where these applications are commonly deployed. The flaw stems from improper handling of specially crafted Word documents that contain malicious content, particularly when these documents are opened or processed by the vulnerable Word application.
The technical nature of this vulnerability involves a memory corruption issue that occurs during the processing of rich text formatting elements within Word documents. When a user opens a maliciously crafted document, the Word application fails to properly validate input data, leading to memory corruption that can be exploited to gain arbitrary code execution privileges. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of how improper input validation can lead to privilege escalation and remote code execution. The vulnerability is particularly dangerous because it can be triggered through social engineering attacks where users unknowingly open malicious documents sent via email or downloaded from compromised websites.
The operational impact of CVE-2021-1716 extends beyond simple code execution, as successful exploitation can lead to complete system compromise and persistent access for attackers. Once executed, malicious code can establish backdoors, escalate privileges, and potentially spread laterally within network environments. This vulnerability aligns with ATT&CK technique T1203, which covers legitimate credentials and privilege escalation methods that attackers use to maintain access. The risk is amplified in enterprise environments where Word is frequently used for document sharing and collaboration, creating multiple attack vectors through email systems, shared drives, and cloud storage platforms. Organizations with outdated Office installations or those that have not applied security patches face particularly high exposure to this vulnerability.
Mitigation strategies for CVE-2021-1716 should focus on immediate patch deployment and implementation of defensive measures. Microsoft released security updates that address this vulnerability, and organizations must prioritize applying these patches across all affected systems. Additionally, implementing application whitelisting policies, disabling macro execution in Word, and configuring email filters to block suspicious attachments can significantly reduce exploitation risk. Network segmentation and monitoring for unusual file access patterns can help detect potential exploitation attempts. Security teams should also consider implementing sandboxing mechanisms for document processing and maintaining regular security assessments to identify unpatched systems. The vulnerability demonstrates the importance of timely security patch management and highlights how seemingly routine applications like word processors can serve as primary attack vectors in sophisticated cyber campaigns.