CVE-2026-55048 in Office
Summary
by MITRE • 07/14/2026
Integer overflow or wraparound in Microsoft Office Excel 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 integer overflow condition that can be exploited within Microsoft Office Excel applications, enabling arbitrary code execution on affected systems. The flaw occurs when Excel processes certain file formats or data structures that trigger integer wraparound behavior during memory allocation or array indexing operations. Such vulnerabilities typically arise from insufficient input validation and boundary checking mechanisms within the application's parsing routines for spreadsheet files.
The technical implementation of this vulnerability involves scenarios where Excel encounters malformed or specially crafted spreadsheet data that causes arithmetic operations to exceed maximum integer limits, resulting in unexpected behavior. When an attacker can control the input data through malicious Excel files or documents, they can manipulate the application into allocating insufficient memory or accessing invalid memory locations. This overflow condition creates opportunities for memory corruption that attackers can leverage to inject and execute malicious code within the context of the running Excel process.
From an operational impact perspective, this vulnerability presents a significant risk to enterprise environments where Microsoft Office applications are widely deployed. Attackers typically exploit such vulnerabilities through social engineering campaigns targeting end-users with malicious Excel documents attached to phishing emails or delivered through compromised websites. The local execution aspect means that successful exploitation does not require network connectivity after initial compromise, allowing attackers to establish persistent access within the target environment. This vulnerability can be particularly dangerous in corporate settings where users frequently open spreadsheet files from untrusted sources.
The mitigation strategies for this vulnerability align with standard secure coding practices and defensive measures recommended by cybersecurity frameworks such as those outlined in the CWE database. Organizations should prioritize timely application of Microsoft security updates and patches that address the specific integer overflow conditions. Additionally, implementing application whitelisting policies, email filtering controls, and user education programs can significantly reduce the attack surface for such exploits. Network segmentation and privilege separation measures provide additional layers of defense against potential exploitation attempts.
This vulnerability type falls under the broader category of memory corruption vulnerabilities classified in the MITRE ATT&CK framework as part of the code injection techniques, specifically targeting the execution phase of an attack lifecycle. The integer overflow condition creates a pathway for attackers to achieve arbitrary code execution without requiring elevated privileges, making it particularly attractive for initial compromise activities. Security monitoring should focus on detecting unusual memory allocation patterns or process behavior that might indicate exploitation attempts. Organizations should also implement automated patch management processes to ensure rapid deployment of security updates across their Microsoft Office environments.
The underlying cause of this vulnerability demonstrates the importance of proper integer handling in software development, particularly when dealing with user-supplied data. Modern secure coding practices emphasize bounds checking, input validation, and overflow detection mechanisms that can prevent such conditions from being exploited. The vulnerability underscores the necessity of comprehensive security testing including fuzzing techniques and static code analysis to identify similar integer overflow conditions before they can be exploited by malicious actors. Regular security assessments and penetration testing should include evaluation of application handling of malformed data inputs to proactively identify potential integer overflow scenarios that could lead to privilege escalation or arbitrary code execution.