Description

Use after free in Microsoft Office allows an unauthorized attacker to execute code locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:53.830Z",
  "pubdate": "2026-08-11T17:18:53.830Z",
  "executiveSummary": "This vulnerability is classified as a use-after-free weakness affecting Microsoft Office. The flaw resides in memory management routines within the application suite, specifically handling dynamically allocated objects.\nSuccessful exploitation of this vulnerability allows an unauthorized local attacker to achieve arbitrary code execution on the target system.\nThe risk implications are severe, as an attacker who successfully exploits this flaw can execute code in the context of the currently logged-in user, potentially leading to a full compromise of the user session and local system integrity.\nThe attack vector involves local execution, requiring the user to interact with a specially crafted file or document processed by Microsoft Office.\nNo specific authentication requirements are indicated for the local exploitation vector beyond the capability to deliver and execute the malicious payload or document locally.",
  "technicalDetails": "The root cause of the vulnerability is a use-after-free condition within Microsoft Office memory management. A use-after-free defect occurs when a program continues to use a pointer after the memory region to which it refers has been deallocated or freed.\nWhen the affected component in Microsoft Office frees an object's memory without appropriately nullifying the associated pointers, a dangling pointer remains. If the application subsequently attempts to reference this dangling pointer, it interacts with memory that may have been reallocated for another purpose.\nThe exploitation method relies on heap manipulation and state corruption. An attacker can craft a malicious document designed to trigger the premature deallocation of a specific memory object while retaining a reference to it. By strategically spraying the heap or controlling subsequent memory allocations, the attacker can replace the freed memory structure with controlled malicious data or shellcode.\nThe step-by-step attack flow proceeds as follows: First, the attacker delivers a malformed file designed to interact with the vulnerable Microsoft Office component. Second, parsing the file triggers the improper handling of object lifecycles, causing the application to free a memory chunk while retaining internal references. Third, the attacker orchestrates heap grooming to place malicious payload structures into the newly freed memory location. Finally, when the application dereferences the dangling pointer, it executes the attacker-controlled instructions or function pointers residing at that address.\nThe vulnerable component involves the memory handling logic within Microsoft Office file parsers or rendering engines. The privilege requirements are limited to standard local user access, and the attack surface requires local file interaction or user-assisted opening of a crafted file."
}