CVE-2026-55035 in Office
Summary
by MITRE • 07/14/2026
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical out-of-bounds read flaw within Microsoft Office applications that enables local attackers to extract sensitive information from memory locations outside the intended data boundaries. The technical implementation of this vulnerability typically occurs when Office applications fail to properly validate array indices or buffer limits during document processing operations, allowing malicious actors to access memory regions containing confidential data such as encryption keys, user credentials, or system information. The flaw operates at the application level where Office components like Word, Excel, or PowerPoint process potentially malicious documents, and the out-of-bounds read occurs when these applications attempt to access memory locations that have not been properly validated for bounds checking. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, which is classified as a weakness in software design that directly enables unauthorized information disclosure. From an operational perspective, this vulnerability creates significant risk for enterprise environments where Office documents are frequently exchanged and processed, potentially allowing attackers to extract sensitive data from system memory through crafted documents or by exploiting the vulnerability during normal document processing activities. The impact extends beyond simple information disclosure as it could enable further exploitation paths including privilege escalation or lateral movement within compromised networks, making this a particularly dangerous flaw in enterprise security contexts where Office applications are widely used and trusted. Microsoft typically addresses such vulnerabilities through patches that implement proper bounds checking mechanisms and input validation procedures that prevent the application from accessing memory locations outside allocated buffers. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter for execution of malicious code, while also aligning with T1003 Credential Access techniques where the information disclosure could lead to credential harvesting. Organizations should implement immediate patch management procedures and consider additional security controls such as application whitelisting, email filtering solutions, and user education programs to reduce the attack surface. The vulnerability demonstrates the importance of robust input validation in office productivity applications and highlights how seemingly benign document processing operations can become vectors for sophisticated information disclosure attacks when proper bounds checking mechanisms are absent from the code implementation. Security teams should monitor for indicators of compromise related to this vulnerability through endpoint detection and response systems that can identify unusual memory access patterns or attempts to read unauthorized memory regions during Office application execution.