Description

Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.5",
  "pubDate": "2026-08-11T17:19:02.360Z",
  "pubdate": "2026-08-11T17:19:02.360Z",
  "executiveSummary": "An out-of-bounds read vulnerability exists within Microsoft Office, which can be leveraged by an unauthorized local attacker to facilitate unauthorized information disclosure. This security flaw compromises memory confidentiality by allowing unauthorized read operations beyond the allocated buffer boundaries of the affected software component. The impact is primarily restricted to local information disclosure, potentially exposing sensitive memory contents, which may include user data or critical system artifacts residing in adjacent memory spaces. Affected systems comprise vulnerable installations of Microsoft Office. The risk implications involve the potential leakage of sensitive heap or stack data that could be chained with other vulnerabilities to bypass modern exploit mitigations such as ASLR. Attacker capabilities are limited to local access vectors, requiring the target user to open a specially crafted malicious file or interact with a compromised document locally. Exploitation requirements typically mandate that the victim opens the malicious payload using an unpatched, vulnerable instance of the software. No direct remote code execution or privilege escalation capabilities are inherent to this specific out-of-bounds read primitive, but the intelligence gathered from the disclosure could facilitate subsequent attack phases.",
  "technicalDetails": "The vulnerability stems from an out-of-bounds read flaw within Microsoft Office, specifically occurring when the application parses malformed file structures or handles improperly bounded data buffers during document rendering and parsing operations. The root cause lies in insufficient bounds checking and input validation logic within the vulnerable component responsible for processing specific file format elements. When the application attempts to read data from a designated offset, failure to properly validate the size and boundaries of the input against the allocated memory buffer results in the reading of adjacent memory regions.\nThe exploitation method relies on supplying a crafted document containing malicious structural metadata or malformed object dimensions. Upon parsing the malicious file, the vulnerable component calculates an invalid read address pointing outside the legitimate buffer boundaries. The attack flow proceeds as follows: First, the unauthorized local attacker delivers the malicious document to the target system via local storage, removable media, or secondary file transfer methods. Second, the user opens the file using the affected Microsoft Office application. Third, the parsing engine processes the malformed structures without adequate boundary verification. Fourth, the application executes an out-of-bounds memory read operation, accessing sensitive data stored in adjacent heap or stack memory structures. Finally, depending on how the application handles the retrieved data, the leaked information may be exposed via error messages, application logs, or improperly sanitized output structures visible to the local process.\nThe vulnerability requires local access and does not inherently facilitate remote network exploitation without user interaction. The vulnerable component operates within the context of the locally logged-in user, meaning the attack executes with the standard privilege level of the user running the affected application. Network exposure is non-existent unless combined with other transport-vector flaws. Post-exploitation impact is strictly confined to unauthorized information disclosure, wherein the attacker gains visibility into memory contents that should otherwise remain isolated and protected."
}