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": "2026-08-11T17:19:10.010Z",
  "pubdate": "2026-08-11T17:19:10.010Z",
  "executiveSummary": "This security analysis evaluates an improper input validation vulnerability residing within Microsoft Office.\nThe vulnerability allows an unauthorized local attacker to successfully execute an information disclosure attack, compromising the confidentiality of sensitive local data.\nThe affected product is Microsoft Office, which fails to properly validate user-supplied or file-based input during document parsing and processing routines.\nThe risk implications are significant, as successful exploitation enables unauthorized actors to harvest sensitive information from the local system without requiring elevated privileges.\nAttacker capabilities are constrained to unauthorized local access, meaning the adversary must already possess execution capabilities or local interaction vectors to supply the maliciously crafted input.\nNo specific preconditions or complex privileges are explicitly detailed beyond the baseline requirement of triggering the improper input validation routine within the application context.\nOrganizations utilizing vulnerable versions of Microsoft Office face potential data leakage risks if local threat actors successfully induce the parsing of maliciously structured files or input streams designed to trigger the flaw.",
  "technicalDetails": "The root cause of the vulnerability stems from improper input validation within Microsoft Office components responsible for parsing, interpreting, and rendering file formats or internal data structures.\nWhen Microsoft Office processes a specifically crafted input containing anomalous or malformed parameters, the lack of rigorous boundary checking and sanitization leads to an insecure state during execution.\nThe vulnerable component resides within the core document parsing and input handling subsystems of Microsoft Office, which process untrusted data streams without adequately validating input length, format, or semantic constraints.\nExploitation is achieved when an unauthorized local actor supplies maliciously engineered input or a crafted file to the target application, tricking the parser into reading memory regions or local files outside the intended security boundaries.\nThe attack flow proceeds as follows: First, the attacker crafts a malicious payload designed to exploit the improper input validation flaw. Second, the attacker introduces this input to the vulnerable Microsoft Office application locally, either by placing a file in a specific directory or executing the application with malicious parameters. Third, the application parses the input, failing to validate the data structures correctly. Fourth, the insecure processing logic triggers a memory or file read condition, exposing sensitive local information back to the execution context.\nAuthentication requirements are nonexistent for local execution, and the vulnerability can be leveraged by unauthorized entities operating with standard user privileges on the local host.\nNetwork exposure is not a prerequisite for this vulnerability, as the attack vector is strictly local, manifesting entirely within the local execution environment of the affected system.\nThe payload behavior centers around leveraging the parsing engine's failure to return unauthorized data disclosures, potentially leaking sensitive memory contents or local files accessible to the application context.\nThe post-exploitation impact is characterized by unauthorized information disclosure, enabling the adversary to gather intelligence, internal system paths, or sensitive data artifacts residing on the local machine for subsequent attack phases."
}