CVE-2025-53759 in Excel
Summary
by MITRE • 08/12/2025
Use of uninitialized resource in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/16/2025
This vulnerability resides in Microsoft Office Excel software where an uninitialized resource is improperly handled during the processing of certain file formats. The flaw occurs when Excel attempts to parse maliciously crafted spreadsheet files that contain malformed data structures, leading to the exploitation of memory management issues within the application's parsing engine. The uninitialized resource typically refers to memory locations or variables that are not properly initialized before being used, creating potential entry points for code execution attacks. This vulnerability specifically affects the Excel application's ability to safely handle external data sources or complex spreadsheet elements that trigger the problematic code path.
The technical implementation of this vulnerability involves the exploitation of memory corruption patterns that arise when Excel processes certain data types or formatting elements in spreadsheet files. Attackers can craft malicious .xlsx or .xls files that contain specially constructed data sequences designed to trigger the uninitialized resource condition. When a user opens such a file, the Excel application attempts to parse the data and inadvertently executes code from the uninitialized memory location. This type of vulnerability is classified under CWE-457 as "Use of Uninitialized Variable" and represents a critical memory safety issue that allows for arbitrary code execution in the context of the running Excel process. The vulnerability demonstrates characteristics of a heap-based buffer overflow or similar memory corruption patterns that are commonly exploited in office application attacks.
The operational impact of CVE-2025-53759 is significant as it enables attackers to execute malicious code with the privileges of the targeted user, potentially leading to full system compromise. The attack vector requires user interaction through opening a malicious file, making social engineering aspects crucial for successful exploitation. Once executed, the code can perform various malicious activities including data exfiltration, system reconnaissance, privilege escalation, or installation of additional malware components. The vulnerability affects multiple versions of Microsoft Office Excel and can be particularly dangerous in enterprise environments where users frequently open spreadsheet files from external sources or email attachments. Security researchers have noted that this vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, as the exploitation allows for command execution within the target system.
Mitigation strategies for this vulnerability should include immediate application of Microsoft security patches and updates as soon as they become available through the Microsoft Update Catalog or Windows Update services. Organizations should implement strict email filtering policies to prevent users from opening suspicious spreadsheet files and consider deploying application whitelisting solutions to restrict execution of unauthorized Office applications. Network administrators should monitor for unusual file access patterns or attempts to execute code through Office applications. Additionally, users should be trained to recognize potential social engineering attempts and avoid opening attachments from untrusted sources. System hardening measures such as enabling Data Execution Prevention and using Windows Defender Application Control can provide additional layers of protection. The vulnerability also highlights the importance of maintaining up-to-date security configurations and regularly reviewing access controls to minimize potential attack surface exposure.