CVE-2026-55028 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 • 07/15/2026
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 practices within the office suite's parsing mechanisms for various document formats including word processing files, spreadsheets, and presentation documents. When processing malformed or specially crafted Office documents, the application fails to properly bounds-check array accesses or buffer operations, allowing an attacker to read memory locations beyond the intended data boundaries. This type of vulnerability aligns with common weakness enumeration CWE-129 which specifically addresses improper validation of length of buffers, and can be categorized under the broader ATT&CK technique T1059.005 for command and scripting interpreter usage in exploitation scenarios.
The operational impact of this vulnerability extends beyond simple information disclosure as it provides attackers with potential access to sensitive data such as memory contents, encryption keys, or other confidential information stored in the application's memory space. Attackers can leverage this flaw by delivering malicious Office documents through phishing campaigns, social engineering tactics, or compromised websites that automatically trigger the vulnerable code path when users open the documents. The local privilege escalation aspect of this vulnerability means that even if the initial attack vector doesn't provide elevated privileges, the information disclosure capability could enable further exploitation attempts such as credential harvesting, system reconnaissance, or crafting more sophisticated attacks against the target environment.
Mitigation strategies for this vulnerability should encompass multiple layers of protection including immediate deployment of Microsoft security patches and updates to address the root cause in the Office application code. System administrators should implement strict document handling policies that restrict opening of untrusted Office files, particularly those received via email or downloaded from unknown sources. Network segmentation and application whitelisting controls can help limit the potential attack surface by preventing unauthorized Office applications from running on critical systems. Additionally, endpoint detection and response solutions should be configured to monitor for suspicious memory access patterns or anomalous behavior indicative of out-of-bounds read attempts. Regular security awareness training for end users remains crucial in identifying potential social engineering attempts that might deliver malicious Office documents containing this vulnerability. The remediation process must also include comprehensive monitoring of system logs and network traffic for signs of exploitation attempts, as well as maintaining current threat intelligence feeds to identify known malicious Office document samples associated with similar vulnerabilities.