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": "2026-08-11T17:18:54.203Z",
  "pubdate": "2026-08-11T17:18:54.203Z",
  "executiveSummary": "This vulnerability is classified as a heap-based buffer overflow affecting Microsoft Office.\nThe security flaw enables an unauthorized attacker to achieve local code execution on the targeted system.\nThe primary impact of successful exploitation includes complete compromise of the affected application process, integrity violation, and potential system-wide compromise depending on the execution context and user privileges.\nThe affected product is Microsoft Office, which processes complex file formats and untrusted input streams.\nRisk implications are significant due to the prevalence of Microsoft Office in enterprise environments and the capability for local code execution upon parsing malformed files or interacting with vulnerable components.\nAttacker capabilities require local access or user interaction to process a maliciously crafted input or document.\nExploitation requirements include delivering the malicious payload to the victim system and inducing the vulnerable Microsoft Office component to parse the invalid data structure, thereby triggering the memory corruption condition.",
  "technicalDetails": "The root cause of the vulnerability stems from improper boundary checks within memory allocation and buffer management routines in Microsoft Office during the parsing of complex data structures.\nSpecifically, a heap-based buffer overflow occurs when the application allocates an insufficient amount of heap memory or fails to properly validate the size of incoming data prior to writing it into a heap-allocated buffer.\nThe vulnerable component resides within the core file parsing and data processing modules of Microsoft Office responsible for handling specific document formats or embedded objects.\nAuthentication requirements are nonexistent for local exploitation, as the flaw is triggered through data processing rather than network authentication protocols.\nPrivilege requirements are minimal, requiring only standard user privileges to open a malformed file or interact with the vulnerable application instance locally.\nNetwork exposure is not strictly required for local exploitation vectors, though the payload delivery mechanism may involve network-based vectors such as email attachments or shared drives.\nThe exploitation method involves supplying a specially crafted input file designed to exceed the bounds of the targeted heap buffer, leading to a heap corruption condition.\nThe step-by-step attack flow begins when an unauthorized attacker crafts a malicious file containing oversized or malformed data structures designed to target the heap allocation routine.\nNext, the victim opens the file using a vulnerable version of Microsoft Office.\nAs the application parses the file, the vulnerable component allocates a heap buffer whose size is miscalculated or mismatched relative to the incoming data stream.\nSubsequent copy or write operations write data past the boundary of the allocated heap chunk, overwriting adjacent heap metadata and critical application structures.\nAn advanced attacker can carefully manipulate the adjacent heap layout to achieve deterministic memory corruption, facilitating arbitrary code execution.\nPayload behavior following successful exploitation involves executing malicious shellcode or arbitrary binaries within the security context of the logged-on user.\nPost-exploitation impact includes unauthorized local code execution, potential privilege escalation if auxiliary kernel or service vulnerabilities are chained, installation of persistent malware, and lateral movement within the compromised network environment."
}