Description

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

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-11T17:18:54.633Z",
  "pubdate": "2026-08-11T17:18:54.633Z",
  "executiveSummary": "A heap-based buffer overflow vulnerability exists within Microsoft Office, potentially enabling an unauthorized, local attacker to achieve arbitrary code execution on targeted systems.\nThe vulnerability resides in the memory management handling of specific file formats or data structures parsed by Microsoft Office components.\nSuccessful exploitation of this flaw allows malicious actors to execute arbitrary code within the security context of the currently logged-in user, leading to potential system compromise, data exfiltration, or lateral movement.\nThe risk implication is critical due to the ubiquitous deployment of Microsoft Office across enterprise environments and the possibility of weaponization via malicious documents.\nAttacker capabilities are constrained by the privileges of the local user running the vulnerable application, and exploitation typically requires local access or user interaction, such as opening a maliciously crafted file supplied by the attacker.",
  "technicalDetails": "The vulnerability is a heap-based buffer overflow stemming from improper bounds checking and memory allocation routines within Microsoft Office parsers.\nWhen a specially crafted file is processed, the application fails to validate the size of incoming data before writing it to a dynamically allocated heap buffer, leading to a memory corruption condition.\nThe root cause lies in the mishandling of memory operations during the parsing of complex data structures, where attacker-controlled input parameters dictate the size and length of copy operations.\nDuring the attack flow, the victim opens a malicious document designed to trigger the vulnerable parsing routine.\nAs the application attempts to deserialize or process the malformed data, the overflow overwrites adjacent heap metadata or critical application structures.\nAn unauthorized local attacker can manipulate the layout of the heap to achieve deterministic memory corruption, facilitating the overwriting of function pointers or virtual method tables.\nWhen the application subsequently attempts to execute a corrupted pointer, control flow is hijacked, redirecting execution to attacker-supplied shellcode or a return-oriented programming (ROP) chain.\nAuthentication requirements are absent for local exploitation, as the vector relies on file processing rather than network authentication protocols.\nPrivilege requirements are minimal, requiring only standard user rights to launch the application and open the malicious file.\nNetwork exposure is not strictly necessary for direct exploitation if the file is delivered locally, though files are frequently distributed via email or web downloads.\nPost-exploitation impact includes complete compromise of the application process, unauthorized access to user data, and the potential deployment of persistent malware or secondary payloads within the local environment."
}