CVE-2026-97001 in Word
Summary
by MITRE • 10/14/2026
Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Office Word application, specifically manifesting as a heap-based buffer overflow. This type of memory corruption error occurs when a program writes more data to a block of dynamically allocated memory on the heap than it was intended to hold. In the context of Microsoft Office Word, this typically arises during the processing of complex document structures or specific file formats where input validation is insufficient. When an attacker crafts a maliciously formatted document containing oversized fields or malformed objects, they can overwrite adjacent memory locations that contain control data such as function pointers or exception handlers. This overwriting allows for arbitrary code execution with the privileges of the currently logged-in user, effectively granting unauthorized access to the system and potentially leading to full compromise if elevation of privilege techniques are subsequently employed.
From a technical perspective, heap-based buffer overflows differ from stack-based ones in that they affect dynamically allocated memory regions used during runtime operations rather than local variables stored on the call stack. The exploitation mechanism relies on precise manipulation of memory allocation sizes and offsets to achieve reliable control flow hijacking. Modern operating systems employ various mitigations such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR), which make successful exploitation more difficult but not impossible. Attackers often utilize return-oriented programming techniques or exploit specific library vulnerabilities within the Office suite to bypass these protections, ultimately achieving remote code execution capabilities without requiring physical access to the machine beyond initial document delivery via email or network shares.
The operational impact of this vulnerability is severe due to its potential for widespread exploitation through social engineering tactics. Since Microsoft Word is a ubiquitous tool in enterprise and personal environments, attackers frequently distribute malicious documents as attachments in phishing emails or host them on compromised websites for drive-by downloads. Successful exploitation results in the installation of malware, data exfiltration, credential theft, and further lateral movement within networked environments. The ability to execute code locally means that once a user opens the infected document, the attacker gains a foothold equivalent to that user's permissions, which can range from standard user rights to administrative privileges depending on system configuration and group policy settings.
To mitigate this risk, organizations must ensure that all Microsoft Office installations are updated with the latest security patches released by Microsoft. Regular application of cumulative updates is essential as these often include fixes for previously undisclosed vulnerabilities before they become widely known in public databases. Additionally, implementing strict email filtering policies to block suspicious attachments and enabling Protected View can significantly reduce the attack surface. Users should be educated on recognizing phishing attempts and avoiding opening documents from untrusted sources. From a defensive posture perspective, deploying endpoint detection and response solutions that monitor for anomalous process behavior associated with Office applications spawning unexpected child processes can help detect exploitation attempts in real time.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-122, which describes heap-based buffer overflow conditions where memory corruption leads to security vulnerabilities. In terms of the MITRE ATT&CK framework, this flaw facilitates initial access techniques such as Spearphishing Attachment or Drive-by Compromise, and enables execution capabilities categorized under Command and Scripting Interpreter or Native API Execution depending on how the payload is delivered post-exploitation. Understanding these mappings helps in configuring security information and event management systems to detect related indicators of compromise and in prioritizing remediation efforts based on industry-standard risk assessments.