Description

Heap-based buffer overflow in Microsoft Office Access allows an unauthorized attacker to execute code locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:53.333Z",
  "pubdate": "2026-08-11T17:18:53.333Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting Microsoft Office Access. The flaw enables an unauthorized local attacker to achieve arbitrary code execution on the targeted system.\nThe risk implications are severe, as successful exploitation compromises the confidentiality, integrity, and availability of the host operating system under the security context of the currently logged-in user.\nThe attack capabilities require local access to the target system, typically involving the victim opening a maliciously crafted database file or interacting with a vulnerable component of the software.\nNo specific authentication or advanced privileges are inherently required beyond the ability to execute the application locally and process a malformed input file.\nDefensive strategies must focus on applying official vendor updates, enforcing strict file origin controls, and implementing endpoint protection mechanisms to detect anomalous heap manipulation.",
  "technicalDetails": "The vulnerability resides within the heap management architecture of Microsoft Office Access, specifically in the component responsible for parsing and allocating memory for specialized data structures.\nThe root cause stems from improper boundary validation and insufficient length checks during memory allocation operations on the heap. When the application processes a crafted input containing excessively large or improperly formatted data fields, the calculation fails to account for the actual data size.\nThis calculation error results in a heap-based buffer overflow, where incoming data exceeds the boundaries of the allocated heap chunk, subsequently overwriting adjacent heap metadata and adjacent memory regions.\nThe exploitation method requires an unauthorized local attacker to construct a malformed Microsoft Office Access database file. Upon ingestion and processing by the vulnerable parsing routines, the malicious payload corrupts adjacent heap structures.\nBy carefully controlling the size and content of the overflow data, the attacker can manipulate internal function pointers or dynamic memory control blocks.\nThe step-by-step attack flow proceeds as follows: First, the user opens the malicious database file using Microsoft Office Access. Second, the parsing engine encounters oversized data structures within the file format. Third, the allocation routine assigns an insufficiently sized heap buffer. Fourth, the write operation continues past the boundary of the buffer, corrupting adjacent heap memory. Fifth, the application executes a tainted function pointer or processes corrupted heap structures, diverting control flow to attacker-supplied shellcode.\nThe affected component is the Microsoft Office Access database parsing engine. The vulnerability can be exploited locally without prior authentication, provided the user interacts with the malicious artifact.\nThe payload behavior involves executing native machine code within the security context of the application process, potentially leading to privilege escalation, persistent installation of malware, or lateral movement within the local environment."
}