CVE-2026-80089 in Office
Summary
by MITRE • 09/09/2026
Out-of-bounds read in Microsoft Office allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Office suite, specifically categorized as an out-of-bounds read error. This type of memory corruption issue arises when software attempts to access data at a memory address that lies outside the boundaries of the intended buffer or array structure. In the context of document processing applications like Word, Excel, or PowerPoint, such errors typically occur during the parsing and rendering of complex file formats. When an attacker crafts a malicious document containing specially designed content, they can trigger this condition by causing the application to read memory locations that were not allocated for the specific operation. This deviation from expected program flow allows the system to expose internal memory contents that should remain inaccessible to user-level processes or external entities.
From a technical perspective, an out-of-bounds read differs significantly from an out-of-bounds write in its immediate impact on system stability and security goals. While writes can lead to code execution by overwriting critical data structures such as function pointers or return addresses, reads primarily facilitate information disclosure. The attacker leverages this flaw to extract sensitive data residing in the application's memory space. This may include cryptographic keys, session tokens, credentials stored in clipboard history, or other proprietary information processed during document rendering. Because Microsoft Office is a widely deployed productivity tool often used with networked resources and cloud storage services, the ability to read arbitrary memory locations presents a significant risk for data exfiltration over local area networks or the internet.
The operational impact of this vulnerability extends beyond simple data leakage. It undermines the confidentiality integrity pillar of information security by allowing unauthorized parties to gain insights into the internal state of the victim's system. If an organization relies on Microsoft Office for handling sensitive corporate documents, emails containing confidential attachments, or financial reports, a successful exploitation could lead to substantial intellectual property theft or compliance violations under regulations such as GDPR or HIPAA. Furthermore, because this vulnerability is triggered by opening or viewing a malicious file, it often falls into the category of drive-by attacks where social engineering tactics are used to persuade users to open infected documents, thereby increasing the likelihood of successful compromise without requiring direct network access from the attacker's machine initially.
In terms of industry classification standards, this flaw aligns with CWE-125, which defines out-of-bounds read vulnerabilities. It also maps closely to MITRE ATT&CK techniques related to Collection and Exfiltration over C2 channels or local data staging. Specifically, it relates to Tactic TA0008 (Collection) where the attacker gathers information from the target system through methods like screen capture or keylogging if combined with other exploits, but in this specific context, it is primarily a mechanism for Data from Local System via memory scraping techniques often associated with T1057. The exploitation vector typically involves remote code execution prerequisites being bypassed by focusing solely on data retrieval, making detection more challenging as traditional antivirus signatures might not flag the behavior if no malicious payload is executed immediately after the read operation.
Mitigation strategies for this vulnerability require a multi-layered approach involving both technical controls and user awareness. Organizations must ensure that all Microsoft Office installations are updated to the latest versions containing security patches released by Microsoft, which address these memory management errors through improved bounds checking during file parsing processes. Additionally, implementing application control policies such as AppLocker or Windows Defender Application Control can restrict the execution of untrusted scripts and macros often used in conjunction with document-based exploits. Network segmentation should be employed to limit lateral movement if an initial compromise occurs, while endpoint detection and response solutions should monitor for anomalous memory access patterns indicative of exploitation attempts. User training remains critical, emphasizing caution when opening documents from unknown sources or those received via email attachments, as this is the primary delivery mechanism for such attacks.