CVE-2026-55057 in Office
Summary
by MITRE • 07/14/2026
Integer overflow or wraparound in Microsoft Office allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a classic integer overflow condition that can be exploited to achieve local information disclosure within Microsoft Office environments. The flaw occurs when the application processes integer values that exceed their maximum representable range, causing the value to wrap around to a much smaller number through modular arithmetic. This type of vulnerability falls under the CWE-190 category known as "Integer Overflow or Wraparound" and can be classified as a local privilege escalation vector when combined with information disclosure capabilities.
The technical implementation involves Microsoft Office applications handling user-supplied data that gets processed through integer operations without proper bounds checking. When an attacker crafts malicious input that triggers integer overflow conditions during document parsing or rendering processes, the application may behave unpredictably by wrapping integer values to negative numbers or zero, which can then be exploited to access memory locations that should otherwise remain protected. This vulnerability typically manifests when Office applications process files with malformed data structures, particularly in formats such as docx, xlsx, or pptx where complex data parsing occurs.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks within the local system. An attacker who successfully exploits this condition can leverage the overflow to manipulate memory layouts and access sensitive data that may include user credentials, application configuration details, or other confidential information stored in memory. This represents a significant concern for enterprise environments where Microsoft Office is widely deployed, as it could allow an attacker to gather intelligence about system configurations or user activities through carefully crafted malicious documents.
Security mitigations for this vulnerability should focus on implementing robust input validation mechanisms within Office applications, particularly around integer handling operations that process external data. Organizations should ensure timely application of Microsoft security updates and patches that address the specific integer overflow conditions in question. Additionally, implementing application sandboxing techniques and restricting user privileges when opening untrusted documents can help contain potential exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and information gathering through local system exploitation, with potential lateral movement opportunities if the compromised Office instance has access to additional network resources or data stores.
The remediation approach requires Microsoft to implement proper integer overflow detection and handling within their Office applications, ensuring that all arithmetic operations are validated against expected ranges before processing. Security teams should also consider implementing network monitoring to detect unusual patterns of document processing that may indicate exploitation attempts, while maintaining comprehensive patch management procedures to ensure all systems receive timely security updates. This vulnerability underscores the importance of secure coding practices and proper input validation in preventing exploitation of mathematical overflow conditions that can lead to unintended system behavior and information leakage.