CVE-2026-68843 in Word
Summary
by MITRE • 09/08/2026
Use after free in Microsoft Office Word allows an authorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability described involves a use-after-free error within the core processing engine of Microsoft Office Word, specifically affecting how memory is managed during document parsing and rendering operations. This class of flaw typically arises when the application fails to properly nullify pointers after freeing associated memory blocks or continues to reference objects that have already been deallocated by the system's garbage collector or manual memory management routines. In the context of a word processing application, this often occurs during complex layout calculations, object embedding handling, or macro execution where multiple layers of abstraction interact with low-level memory structures. When an attacker crafts a malicious document containing specific malformed data sequences, they can trigger conditions that cause Word to release critical memory resources prematurely while retaining references to those same regions in active processing threads or internal state machines.
From a technical perspective, this defect aligns closely with CWE-416, which defines use-after-free as the practice of using pointers after their associated storage has been freed. The operational mechanism relies on the timing discrepancy between memory deallocation and subsequent pointer dereference. Once the vulnerable code path attempts to access or manipulate data through these dangling pointers, it reads from memory locations that may have already been reallocated for other purposes by the operating system or other processes. This creates a scenario where the content of previously freed memory is exposed to the application logic without proper validation checks. While many use-after-free vulnerabilities are exploited for arbitrary code execution leading to remote code execution capabilities, in this specific instance, the exploitation vector appears constrained to information disclosure rather than full control flow hijacking or privilege escalation.
The primary impact of this vulnerability is local information leakage within the context of the currently logged-in user account. An authorized attacker who can persuade a victim to open a specially crafted Word document could potentially extract sensitive data residing in the adjacent memory regions that were previously allocated and then freed by Word. This disclosed information might include fragments of other documents, clipboard contents, cached credentials stored in memory, or internal application states that reveal structural details about the host system. Because the attack requires user interaction to open the malicious file, it is classified as a local vulnerability with social engineering prerequisites. The attacker must have valid authentication on the target machine and typically needs to trick the victim into opening the payload, which limits the blast radius compared to remote network-based exploits but remains significant for targeted attacks or insider threats.
This behavior maps directly to several entries in the MITRE ATT&CK framework, particularly T1059 Command and Scripting Interpreter if macros are involved in triggering the flaw, and more critically T1005 Data from Local System which covers the collection of data stored on local drives or within memory structures before exfiltration. The vulnerability also relates to CWE-200 Exposure of Sensitive Information to an Unauthorized Actor, highlighting the failure to protect sensitive data during runtime operations. Defense in depth strategies are essential here since mitigating use-after-free issues often requires deep changes to application architecture rather than simple configuration tweaks.
To mitigate this risk, organizations should ensure that Microsoft Office Word is updated with the latest security patches released by Microsoft, which typically include fixes for memory management logic and enhanced bounds checking during document parsing. Enabling Protected View for documents received from untrusted sources can prevent the immediate execution of potentially malicious code paths associated with these flaws. Additionally, restricting macro execution to trusted locations only reduces the attack surface if macros are used as a trigger mechanism. Security teams should also monitor for unusual memory access patterns or anomalies in process behavior that might indicate exploitation attempts using tools designed to detect heap corruption or use-after-free conditions. Regular vulnerability scanning and patch management cycles remain the most effective defense against such zero-day style vulnerabilities until specific mitigations can be deployed at the application level.