CVE-2026-88150 in Word
Summary
by MITRE • 10/14/2026
Use of uninitialized resource in Microsoft Office Word allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described involves the improper initialization of resources within Microsoft Office Word, specifically affecting how the application handles certain document structures or embedded objects when processed from remote sources. This flaw stems from a logic error where memory buffers or internal state variables are accessed before being properly initialized with valid data. In complex applications like word processors that parse intricate file formats such as .docx or legacy .doc files, the parser must allocate and initialize numerous temporary structures to interpret embedded elements, macros, or formatting instructions. When an attacker crafts a malicious document containing specially constructed fields or objects, they can trigger this uninitialized access path during the parsing phase. Because Microsoft Office Word is designed to process documents received over networks via email attachments, shared drives, or web downloads, this vulnerability presents a direct remote code execution vector without requiring user interaction beyond opening the file in some configurations, although typically it requires the victim to open the malicious document.
From a technical perspective, accessing uninitialized memory can lead to unpredictable behavior depending on what data previously occupied that memory location. If an attacker controls the content of adjacent memory or can influence how the application interprets the garbage values left in those uninitialized slots, they may achieve arbitrary code execution by overwriting function pointers, manipulating control flow instructions, or exploiting heap corruption mechanisms inherent in the parsing engine. This type of flaw is often categorized under CWE-457, which defines Use of Uninitialized Variable, and frequently intersects with CWE-120 Buffer Overflow if the uninitialized data leads to writing beyond allocated boundaries. The severity lies in the fact that it bypasses many standard sandboxing mechanisms because the execution occurs within the trusted context of the Office application itself before full security checks or macro restrictions can take effect.
The operational impact of this vulnerability is severe, as successful exploitation allows an unauthorized attacker to execute arbitrary code on the victim's system with the privileges of the current user. This typically results in complete compromise of the affected machine, enabling data theft, installation of malware, creation of backdoors, or use of the compromised host for further lateral movement within a corporate network. Attackers often leverage this initial access to deploy additional payloads such as ransomware, keyloggers, or remote administration tools. Given that Microsoft Office is ubiquitous in enterprise environments, the potential blast radius is significant, affecting not only individual productivity but also organizational security posture and data integrity across departments relying on document sharing workflows.
Mitigation strategies primarily involve applying vendor-supplied patches to update the affected versions of Microsoft Office Word, ensuring that all known flaws related to memory management and parsing logic are corrected. Administrators should enforce strict patch management policies to keep office suites up to date with the latest security updates released by Microsoft. Additionally, organizations can reduce risk by disabling macro execution for documents originating from untrusted sources or external networks through Group Policy settings. Implementing application whitelisting solutions that prevent unauthorized executables from running in Office directories can also limit post-exploitation activities. Users should be trained to exercise caution when opening email attachments and verifying the source of shared documents, while network security controls such as advanced threat protection gateways can inspect incoming files for malicious indicators before they reach end-user devices.