CVE-2026-62870 in Excel
Summary
by MITRE • 08/04/2026
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 08/04/2026
This vulnerability represents a critical use-after-free condition in Microsoft Office Excel that enables remote code execution through network-based attacks. The flaw occurs when the application fails to properly validate memory management during object disposal operations, creating opportunities for attackers to manipulate freed memory regions and inject malicious code. Such vulnerabilities typically arise from inadequate bounds checking mechanisms and improper memory deallocation procedures within the spreadsheet application's parsing engine. The attack vector leverages network connectivity through maliciously crafted Excel files or documents that trigger the vulnerable code path when opened by an affected system. This vulnerability directly maps to common weakness enumeration CWE-416 which specifically addresses use-after-free errors in memory management, where program execution continues to reference memory that has already been freed and potentially reallocated for other purposes.
The operational impact of this vulnerability extends beyond simple code execution capabilities as it provides attackers with persistent access to target systems within corporate environments where Microsoft Office applications are commonly deployed. Attackers can leverage this flaw to establish footholds for broader network infiltration, escalate privileges, or deploy additional malware payloads through the compromised Excel application processes. The vulnerability's remote exploitability means that simply opening a malicious document is sufficient to trigger the attack without requiring physical access or additional authentication credentials. Organizations running Microsoft Office installations across their networks face significant risk exposure since Excel files are frequently shared through email attachments, file servers, and collaboration platforms where such malicious documents can easily propagate.
Mitigation strategies must encompass multiple defensive layers including immediate deployment of Microsoft security patches and updates that address the specific memory management flaw in Excel's object handling routines. Network segmentation and email filtering solutions should be enhanced to detect and quarantine potentially malicious Office documents before they reach end-user systems. Endpoint detection and response mechanisms should monitor for suspicious process behavior patterns associated with use-after-free exploitation attempts, including unusual memory allocation patterns or unexpected code execution within Microsoft Office processes. Security teams should implement strict application control policies that limit user privileges when opening Office documents and consider deploying sandboxing technologies to isolate document processing activities. Additionally, regular security awareness training programs should educate users about the dangers of opening untrusted Excel files from unknown sources while maintaining current threat intelligence feeds to identify emerging exploitation patterns targeting this specific vulnerability class as outlined in various ATT&CK framework techniques for privilege escalation and initial access through malicious document delivery methods.