CVE-2026-70315 in Office
Summary
by MITRE • 08/12/2026
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability represents a critical out-of-bounds read flaw within Microsoft Office applications that enables unauthorized attackers to extract sensitive information from the local system. The technical nature of this vulnerability stems from improper input validation and memory management within the office suite's processing libraries, particularly affecting components responsible for handling various document formats including word processing files, spreadsheets, and presentation documents. When a maliciously crafted document is opened or processed by vulnerable Office applications, the software fails to properly bounds-check array accesses or memory allocations, allowing an attacker to read data from adjacent memory locations beyond intended boundaries.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially expose sensitive system data including credentials, encryption keys, temporary files, and other confidential information stored in memory. Attackers can leverage this flaw through social engineering campaigns targeting end users with malicious documents, or through more sophisticated attacks involving fileless execution techniques that exploit the vulnerability without requiring traditional payload delivery methods. This type of vulnerability aligns with CWE-125 Out-of-bounds Read classification within the Common Weakness Enumeration framework and represents a significant concern for enterprise environments where Microsoft Office remains the primary productivity suite.
The exploitation process typically involves crafting a specially formatted document that triggers the vulnerable code path when processed by Office applications, causing memory reads beyond allocated buffers. This can occur during document parsing operations such as handling corrupted or malformed file structures, embedded objects, or complex formatting elements. The vulnerability demonstrates a classic memory safety issue that has been addressed through various mitigation techniques including address space layout randomization, stack canaries, and improved bounds checking mechanisms in modern software development practices.
Organizations should implement immediate mitigations including deploying Microsoft security patches and updates as soon as they become available, implementing strict email filtering and document validation procedures, and conducting regular security awareness training for users to recognize potentially malicious office documents. Additionally, network segmentation and privilege separation can help limit the potential impact of successful exploitation attempts, while endpoint detection and response solutions should be configured to monitor for suspicious memory access patterns and file processing activities that may indicate exploitation attempts. The vulnerability underscores the importance of maintaining up-to-date software inventory management and implementing robust security controls around document handling processes in enterprise environments.