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": "2026-08-11T17:19:08.917Z",
  "pubdate": "2026-08-11T17:19:08.917Z",
  "executiveSummary": "An out-of-bounds read vulnerability exists in Microsoft Office, posing significant security implications for enterprise environments. The vulnerability allows an unauthorized, locally authenticated attacker to disclose sensitive information by exploiting improper memory handling within the application. Affected systems encompass deployments of Microsoft Office where local file parsing operations fail to enforce strict boundary checks. The primary impact is unauthorized information disclosure, potentially exposing sensitive memory contents, user data, or system metadata to an adversary. Exploitation requires the attacker to possess local access to the target system and interact with the vulnerable application instance, typically by supplying a specially crafted file designed to trigger the memory reading condition. No remote network vector is inherently required for initial exploitation based on the provided parameters. Risk implications include the potential leakage of critical process memory, which could be leveraged in subsequent multi-stage attack chains to bypass defensive controls such as address space layout randomization if combined with other vulnerabilities. Defensive posture requires maintaining rigorous software update hygiene and restricting unauthorized local access.",
  "technicalDetails": "The vulnerability is fundamentally rooted in an out-of-bounds read flaw within Microsoft Office parsing logic, specifically occurring when processing untrusted input or structured file formats without proper validation of buffer boundaries. The vulnerable component fails to correctly verify the size and length parameters of incoming data structures against allocated memory buffers before executing read operations. This condition allows read operations to extend past the intended boundary of the buffer, accessing adjacent memory regions that may contain sensitive application state, residual data from previous operations, or stack structures. From an authentication and privilege perspective, the vulnerability requires local execution context, meaning the attacker must either have direct interactive access to the terminal or execute a routine under low-privilege conditions on the host. Network exposure is localized, as the vulnerability does not inherently facilitate remote code execution or remote information harvesting over standard network protocols without auxiliary attack vectors. The step-by-step attack flow begins with the attacker crafting or utilizing a malformed file that exploits the parsing discrepancy within the vulnerable Microsoft Office component. Upon opening or processing the file, the application invokes the vulnerable parsing routine, which attempts to read data based on corrupted or manipulated index values supplied within the file structure. Because the application lacks sufficient bounds-checking assertions, the read pointer traverses memory regions outside the intended allocation scope. The resulting payload behavior involves the extraction of this out-of-bounds data, which may be reflected back to the user interface, written to local logs, or leaked into application cache files accessible to the adversary. The post-exploitation impact is strictly localized to information disclosure; however, the leaked memory contents can significantly aid an attacker in mapping the process memory layout, identifying base addresses of loaded modules, and planning advanced exploitation strategies requiring precise memory manipulation."
}