CVE-2026-56193 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 unauthorized attackers to extract sensitive information from local system memory. The technical implementation involves improper bounds checking during document processing operations where the application fails to validate array indices or buffer limits before accessing memory locations. Such vulnerabilities typically arise when office applications parse malformed or specially crafted documents that contain malicious data structures designed to trigger memory access violations. The flaw exists in the document parsing engine responsible for handling various file formats including word processing documents, spreadsheets, and presentation files. When a user opens a maliciously constructed document, the application's memory management routines attempt to read beyond allocated buffer boundaries, potentially exposing sensitive data from adjacent memory locations.
The operational impact of this vulnerability extends beyond simple information disclosure as it creates potential pathways for further exploitation within local system environments. Attackers can leverage this primitive to gather credentials, encryption keys, or other confidential data stored in memory regions adjacent to the vulnerable application's heap allocations. This type of vulnerability aligns with CWE-125: Out-of-bounds Read which classifies improper validation of buffer boundaries as a fundamental security weakness in software applications. The attack surface is particularly concerning given that Microsoft Office remains one of the most widely deployed productivity suites globally, increasing the potential for widespread exploitation across enterprise and individual user environments.
From an adversary perspective, this vulnerability fits within the ATT&CK framework under techniques such as T1059.001 Command and Scripting Interpreter: PowerShell and T1566.001 Phishing: Spearphishing Attachment, where attackers might craft malicious office documents designed to trigger information disclosure. The local nature of this vulnerability means that successful exploitation typically requires user interaction through opening a malicious document, though the attack vector can be amplified through social engineering campaigns targeting specific individuals or organizations. Security professionals should note that this vulnerability may be chained with other exploits to achieve more sophisticated attacks, particularly when combined with privilege escalation techniques or information gathering phases.
Mitigation strategies for this vulnerability require immediate patch management implementation from Microsoft security updates, alongside user education regarding safe document handling practices and awareness of phishing attempts. Network segmentation controls and application whitelisting solutions can provide additional defense layers by restricting execution of potentially malicious documents in restricted environments. Regular security assessments should include testing for similar memory corruption vulnerabilities through fuzzing techniques targeting office document parsers, and monitoring network traffic for indicators of exploitation attempts. Organizations should also implement robust endpoint detection and response capabilities to identify anomalous behavior patterns associated with out-of-bounds memory access attempts, particularly when such activities occur during routine document processing operations. The vulnerability underscores the importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against sophisticated attack vectors targeting widely used productivity applications.