CVE-2026-55045 in Office
Summary
by MITRE • 07/14/2026
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical memory safety issue within Microsoft Office applications that enables remote code execution through crafted malicious documents. The out-of-bounds read occurs when the application fails to properly validate array indices or buffer boundaries during document parsing operations, allowing attackers to manipulate memory access patterns that ultimately lead to arbitrary code execution. Such vulnerabilities typically arise from insufficient input validation and boundary checking mechanisms within the office document parser components that handle various file formats including docx, xlsx, and pptx. The flaw exists at the intersection of software security principles and memory management practices, where improper bounds checking allows attackers to read memory locations beyond allocated buffers. This particular vulnerability aligns with common weakness enumerations such as CWE-125 which specifically addresses out-of-bounds read conditions, and represents a prime example of how memory corruption vulnerabilities can be exploited through document-based attack vectors. The operational impact extends significantly beyond simple privilege escalation as it provides attackers with the capability to execute malicious code within the context of the targeted user's session, potentially leading to full system compromise.
The exploitation mechanism typically involves crafting specially formatted office documents that trigger the vulnerable parsing logic when opened by an affected application version. Attackers leverage this primitive to manipulate program flow through memory corruption techniques such as return-oriented programming or direct code injection, bypassing modern security mitigations like address space layout randomization and data execution prevention. The vulnerability affects multiple Microsoft Office products including Word, Excel, and PowerPoint across various operating system versions, making it particularly dangerous due to the widespread use of these applications in enterprise environments. Security researchers have documented similar patterns where attackers construct malicious documents that contain crafted data structures designed to cause buffer overflows or out-of-bounds reads during normal document processing operations.
Organizations should implement immediate mitigations including applying Microsoft security patches and updates as soon as they become available, implementing application whitelisting policies to restrict execution of untrusted office documents, and configuring email filters to block suspicious attachments. Network-based defenses should include sandboxing mechanisms for document handling and monitoring for anomalous behavior patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory safety practices in enterprise software development, highlighting how seemingly minor boundary checking failures can result in critical security breaches. Organizations must also consider implementing endpoint detection and response solutions to identify potential exploitation attempts through behavioral analysis rather than relying solely on signature-based detection methods. This particular vulnerability represents a well-known attack pattern that aligns with tactics described in the attack tree framework, particularly focusing on initial access and execution phases where attackers leverage application vulnerabilities to establish persistent access to target systems.