Description

Improper input validation in Microsoft Office allows an unauthorized attacker to disclose information locally.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "5.5",
  "pubDate": "2026-08-11T17:19:08.790Z",
  "pubdate": "2026-08-11T17:19:08.790Z",
  "executiveSummary": "This security analysis evaluates an improper input validation vulnerability within Microsoft Office that enables unauthorized local information disclosure. The vulnerability exposes sensitive local system data to malicious actors who successfully interact with improperly sanitized input vectors within the application. The primary impact of this security flaw is the unauthorized read access to internal system resources or user files, potentially leaking confidential information that aids in subsequent compromise phases. Affected systems encompass deployments of Microsoft Office where input validation routines fail to properly restrict parsing operations. The risk implications are moderate to high depending on the sensitivity of the exposed data and the local security context of the victim. Attacker capabilities are restricted to local access vectors, requiring the execution of malicious payloads or the processing of specially crafted files on the target system. Exploitation prerequisites generally involve local execution capabilities or user interaction, such as opening a maliciously formatted document designed to trigger the input validation failure. Remediation requires the application of official vendor patches designed to enforce strict input sanitization and boundary checks within the affected components of Microsoft Office.",
  "technicalDetails": "The vulnerability resides in the input validation subsystem of Microsoft Office, specifically in how the application parses and processes specific file structures or parameters. The root cause is categorized as improper input validation, where the software fails to adequately verify the boundaries, type, or content of user-supplied data before passing it to internal processing routines. This lack of stringent sanitization allows malicious input to bypass security controls and interact with underlying system APIs or memory spaces in unintended ways. The vulnerable component is tied to the document parsing engine responsible for interpreting specific embedded elements or structural properties within Microsoft Office file formats. Exploitation requires the attacker to have local access to the target system or the ability to deliver a specially crafted file to the victim, requiring user interaction to initiate the parsing process. Authentication requirements are minimal to none within the local context, as the flaw is triggered during standard document rendering or processing by an authenticated user session. The attack flow commences when the vulnerable Microsoft Office application ingests a maliciously crafted file containing anomalous input data designed to exploit the validation weakness. As the parsing engine processes the malformed structures, the lack of proper input validation leads to an out-of-bounds read or an insecure file reference resolution. This flaw allows the application to inadvertently read memory contents or local files that should otherwise be restricted from access. The payload behavior centers on extracting localized data and exfiltrating it or returning it through application error handling mechanisms, user interface displays, or covert channels accessible to the local process. Post-exploitation impact is strictly confined to local information disclosure, wherein the attacker gains visibility into sensitive user data, configuration files, or internal system details that can be leveraged to mount secondary attacks, such as privilege escalation or targeted social engineering campaigns."
}