CVE-2026-70311
Summary
by MITRE • 08/11/2026
Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/11/2026
This vulnerability represents a critical use-after-free condition in Microsoft Office Word that enables remote code execution through crafted malicious documents. The flaw occurs when the application fails to properly validate memory references after objects have been freed, creating opportunities for attackers to manipulate heap memory and redirect execution flow. This type of vulnerability typically arises from improper memory management practices where developers do not adequately track object lifecycles or validate pointer references before dereferencing them.
The technical implementation involves a scenario where Word processes a specially crafted document containing malicious embedded content that triggers an arbitrary code execution path. When the application encounters certain malformed data structures, it may free memory associated with specific objects while still maintaining pointers to those locations. Attackers can exploit this by carefully crafting input that causes the application to reuse freed memory regions, potentially allowing them to inject and execute malicious code within the Word process context.
From an operational perspective, this vulnerability poses significant risk as it enables attackers to achieve local privilege escalation without requiring user interaction beyond opening a malicious document. The attack vector typically involves social engineering campaigns where users are tricked into opening compromised files that contain embedded exploits. The vulnerability affects multiple versions of Microsoft Office Word and can be particularly dangerous in enterprise environments where document sharing is common. Security researchers have identified this as a high-severity issue under the Common Weakness Enumeration framework with CWE-416 indicating the specific weakness of use-after-free conditions.
The exploitation process often involves crafting Office documents with malicious OLE objects or embedded macros that trigger memory corruption when processed by Word's rendering engine. Attackers may leverage this vulnerability in targeted campaigns against specific organizations, using techniques such as spear phishing to deliver malicious documents. The ATT&CK framework categorizes this type of vulnerability under privilege escalation and defense evasion tactics, where adversaries use memory corruption exploits to gain elevated privileges and maintain persistence within compromised systems.
Mitigation strategies include implementing strict application whitelisting policies that restrict execution of unsigned Office documents, regularly updating Microsoft Office installations to patch known vulnerabilities, and deploying advanced threat protection solutions that can detect suspicious document behaviors. Organizations should also consider enabling Office macro security settings to prevent automatic execution of potentially malicious code, while maintaining comprehensive monitoring for unusual memory access patterns or process behavior anomalies. Microsoft recommends immediate deployment of security patches and implementing additional administrative controls such as disabling unnecessary Office features that could be exploited by attackers.