CVE-2026-97742 in Excel
Summary
by MITRE • 10/14/2026
Stack-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability described constitutes a critical security flaw within the Microsoft Office Excel application, specifically manifesting as a stack-based buffer overflow condition that can be exploited remotely via network vectors. This type of vulnerability arises when a program writes more data to a fixed-length block of memory allocated on the call stack than it is intended to hold. In the context of Excel, this typically occurs during the processing of specially crafted files or maliciously formatted content embedded within documents. When an attacker constructs input that exceeds the buffer's capacity without proper bounds checking, the excess data overwrites adjacent memory locations on the stack. This overwrite can corrupt critical control flow information, such as return addresses and saved frame pointers, thereby allowing the attacker to redirect the execution flow of the application.
From a technical perspective, this flaw aligns with Common Weakness Enumeration identifier CWE-121, which defines stack-based buffer overflow. The exploitation mechanism relies on precise memory layout manipulation, often involving techniques like Return-Oriented Programming or direct shellcode injection if Data Execution Prevention is bypassed or disabled. Because the vulnerability allows for arbitrary code execution, it represents a severe compromise of system integrity and confidentiality. An unauthorized attacker who successfully exploits this flaw can execute commands with the same privileges as the current user, potentially leading to full system takeover depending on the context in which Excel is running.
The operational impact of this vulnerability is significant due to its remote exploitable nature over a network. Attackers do not need physical access or local account credentials; instead, they can deliver malicious payloads through various vectors such as phishing emails containing infected attachments, compromised websites hosting exploit kits, or shared network drives with maliciously crafted spreadsheet files. Once executed, the malware installed by this vulnerability may establish persistence mechanisms, exfiltrate sensitive data, install additional backdoors, or participate in botnet activities. The ability to execute code over a network makes this one of the most dangerous classes of vulnerabilities for enterprise environments where users frequently open documents from external sources.
Mitigation strategies must focus on both technical controls and user awareness. Organizations should ensure that Microsoft Office applications are updated with the latest security patches released by vendor, as these updates typically include fixes for buffer overflow conditions through improved input validation and memory management routines. Additionally, implementing application whitelisting can prevent unauthorized or untrusted scripts from running within office environments. Users must be trained to exercise caution when opening files received via email or downloaded from untrusted sources, verifying the source before interaction. Network-level defenses such as intrusion detection systems should also be configured to detect and block traffic patterns associated with known exploitation attempts targeting this specific vulnerability class.