CVE-2026-63526 in Office
Summary
by MITRE • 08/11/2026
Stack-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 08/12/2026
A stack-based buffer overflow vulnerability in Microsoft Office presents a critical security risk that enables unauthorized attackers to execute arbitrary code on compromised systems. This flaw occurs when the application fails to properly validate input data length during stack operations, allowing malicious actors to overwrite adjacent memory locations beyond the allocated buffer boundaries. The vulnerability typically manifests when Office applications process specially crafted documents or files that contain oversized data structures, leading to unpredictable memory corruption and potential code execution.
The technical implementation of this attack vector relies on manipulating input parameters that are processed by Microsoft Office components such as Word, Excel, or PowerPoint. When these applications encounter malformed data during document parsing or file processing operations, the stack memory layout becomes compromised, enabling attackers to overwrite return addresses, function pointers, or other critical control data structures. This memory corruption can be exploited to redirect program execution flow and inject malicious payload code that executes with the privileges of the affected Office application process.
The operational impact of such vulnerabilities extends beyond simple local code execution, as they often serve as initial access vectors for more sophisticated attack chains. Attackers frequently leverage these flaws in conjunction with other exploitation techniques to achieve persistent system compromise, data exfiltration, or lateral movement within network environments. The vulnerability's exploitability is enhanced when Office applications are configured to automatically open or process files from untrusted sources, making it particularly dangerous in enterprise environments where users regularly handle external documents and attachments.
From a cybersecurity framework perspective, this vulnerability aligns with common weakness enumeration cw 121 which specifically addresses buffer overflow conditions that occur when data is written to a buffer without proper bounds checking. The attack pattern follows established techniques documented in the mitre att&ck framework under tactics such as initial access and execution, where adversaries leverage software vulnerabilities to establish footholds within target systems. Security professionals should consider this vulnerability alongside other common attack vectors including phishing campaigns, social engineering, and zero-day exploits that target similar application flaws.
Effective mitigation strategies include implementing comprehensive patch management programs that ensure timely deployment of microsoft security updates, configuring application whitelisting policies to restrict execution of untrusted code, and employing sandboxing technologies that isolate Office applications from critical system resources. Organizations should also consider deploying network-based intrusion detection systems capable of identifying malicious traffic patterns associated with exploitation attempts, while maintaining regular security assessments to identify potential attack surfaces that could be leveraged for similar vulnerabilities. Additional protective measures include user education programs that emphasize safe document handling practices and the implementation of email filtering solutions that can detect potentially malicious attachments before they reach end users.