CVE-2026-64904 in Office
Summary
by MITRE • 08/11/2026
Access of resource using incompatible type ('type confusion') in Microsoft Office allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/11/2026
Type confusion vulnerabilities represent a critical class of software flaws that occur when a program uses a resource with an inappropriate data type, often leading to memory corruption and potential code execution. This particular vulnerability exists within Microsoft Office applications and stems from improper handling of object types during runtime operations. The flaw manifests when the application processes user-supplied data without adequate validation of data types, allowing attackers to manipulate object references in ways that bypass normal type safety mechanisms. Such issues typically arise from insufficient input sanitization and weak object model implementations where the software fails to properly distinguish between different data structures or objects during processing.
The technical exploitation of this vulnerability requires an attacker to craft malicious Office documents that trigger specific parsing sequences within the application's object handling code. When Microsoft Office attempts to process these malformed objects, it incorrectly interprets memory locations as different data types than originally allocated, creating opportunities for arbitrary code execution. The underlying mechanism often involves heap corruption through buffer overflows or use-after-free conditions that occur when type confusion allows attackers to manipulate object vtables or function pointers. This class of vulnerability falls under the common weakness enumeration CWE-461 which specifically addresses "Use of a Non-Standard Data Type" and is frequently associated with memory safety issues in complex software applications.
The operational impact of this vulnerability extends beyond simple privilege escalation as it enables attackers to execute malicious code with the privileges of the targeted user account. Local code execution allows adversaries to install malware, modify system files, establish persistence mechanisms, or exfiltrate sensitive data without requiring network connectivity for initial compromise. The attack surface includes various Office file formats such as docx, xlsx, pptx, and others that may be processed through the vulnerable parsing components. Attackers typically leverage social engineering techniques to deliver malicious documents via email attachments or compromised websites, where user interaction triggers the exploitation sequence.
Mitigation strategies for this vulnerability encompass multiple layers of defense including immediate patch management with Microsoft security updates, implementation of application control policies such as those defined in the MITRE ATT&CK framework under the 'Application Whitelisting' tactic, and enhanced email filtering to prevent delivery of potentially malicious Office documents. System administrators should also consider disabling unnecessary Office features such as macro execution and automatic content loading to reduce attack surface. Network segmentation and monitoring solutions can help detect anomalous behavior indicative of exploitation attempts, while regular security assessments should verify that all Office installations remain current with security patches. The vulnerability underscores the importance of robust type checking mechanisms and proper memory management practices in enterprise software development, particularly for applications handling untrusted data inputs.