CVE-2026-47642 in Office
Summary
by MITRE • 07/14/2026
Use after free in Microsoft Office Excel allows an unauthorized attacker to execute code locally.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical use-after-free condition in Microsoft Office Excel that enables remote code execution through maliciously crafted spreadsheet files. The flaw occurs when the application fails to properly manage memory references after objects have been freed, creating opportunities for attackers to manipulate heap memory and inject malicious code into the running process. Such vulnerabilities typically arise from inadequate bounds checking and memory management practices during object lifecycle handling within the spreadsheet engine.
The technical exploitation involves crafting a malicious excel file that triggers the use-after-free condition when opened or processed by the vulnerable application. Attackers can leverage this weakness to execute arbitrary code with the privileges of the targeted user, potentially leading to full system compromise. The vulnerability is particularly dangerous because it can be delivered through email attachments or web downloads, making it an attractive target for social engineering campaigns. According to the common weakness enumeration framework, this corresponds to CWE-416 which specifically addresses use-after-free vulnerabilities where memory is accessed after it has been freed.
The operational impact of this vulnerability extends beyond simple code execution as it can facilitate privilege escalation attacks, data exfiltration, and persistent backdoor installations within corporate networks. Excel applications are widely used across enterprise environments, making this vulnerability particularly attractive to threat actors seeking broad system access. The attack surface is significantly expanded because the vulnerability can be triggered through multiple vectors including automated processing of documents, shared network drives, or even when opening seemingly benign files in trusted contexts.
Security mitigations for this vulnerability should include immediate deployment of Microsoft security patches and updates, implementation of application whitelisting policies to restrict execution of untrusted Office files, and enhanced email filtering to detect potentially malicious attachments. Network segmentation and monitoring for suspicious file access patterns can help identify exploitation attempts. Organizations should also consider disabling unnecessary Excel features such as macros and external data connections to reduce attack surface. From an ATT&CK framework perspective, this vulnerability maps to initial access and execution phases where adversaries leverage application flaws to establish footholds within target environments, potentially transitioning to lateral movement and privilege escalation activities.
The remediation process requires comprehensive system hardening including regular patch management procedures, user education about suspicious file attachments, and implementation of layered security controls. Organizations should also conduct regular vulnerability assessments targeting Office applications and implement automated threat hunting capabilities to detect potential exploitation attempts. Continuous monitoring of system logs for unusual Office application behavior can help identify compromise indicators before full system takeover occurs.