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": "2026-08-11T17:18:52.600Z",
  "pubdate": "2026-08-11T17:18:52.600Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within Microsoft Office Access, potentially enabling an unauthorized local attacker to achieve arbitrary code execution. The flaw resides in memory management routines handling specific file parsing operations within the application. If successfully exploited, an adversary can manipulate heap memory structures to execute arbitrary code with the privileges of the targeted user session. The attack vector requires the victim to open a maliciously crafted file using the vulnerable software. The implications of successful exploitation include full compromise of the local application context, potential data exfiltration, and lateral movement within the host environment. Risk mitigation relies heavily on applying official vendor updates, restricting the execution of untrusted files, and implementing defensive file-handling policies.",
  "technicalDetails": "The vulnerability is classified as a heap-based buffer overflow stemming from improper bounds checking during the processing of specialized data structures within Microsoft Office Access. Specifically, the vulnerable component fails to adequately validate the size parameters of input data copied into dynamically allocated heap buffers during file parsing operations. An unauthorized attacker can construct a malformed file containing carefully structured payload data designed to exceed the allocated buffer capacity upon ingestion by the application.\nExploitation occurs when a user opens the malicious file via Microsoft Office Access. The parsing engine reads the oversized input and writes beyond the boundaries of the heap-allocated memory region. This out-of-bounds write corrupts adjacent heap metadata, function pointers, or critical application objects. By precisely controlling the overflow data, the attacker can manipulate heap structures to achieve arbitrary memory overwrite primitives. Subsequent execution flow redirection occurs when the application invokes corrupted function pointers or virtual method tables, allowing the injected shellcode or payload to execute under the security context of the logged-in user.\nThe attack vector is local, requiring the target to process a locally stored or transferred malicious file, as network exposure depends entirely on social engineering or secondary delivery mechanisms such as email or shared drives. Authentication is not required to construct the malicious file, and privilege requirements are limited to standard user interaction in opening the document. Post-exploitation impact encompasses localized code execution, potential escalation if coupled with secondary local privilege escalation vulnerabilities, and full access to user-accessible databases and associated system resources managed by Microsoft Office Access."
}