CVE-2026-50314 – Microsoft Office Remote Code Execution Vulnerability

A use-after-free vulnerability in Microsoft Office allows an unauthorized attacker to execute arbitrary code on a local system. Successful exploitation requires a user to open a specially crafted Office file, and Microsoft confirms that the Preview Pane is also an attack vector. Security updates have been released for affected Microsoft Office products across Windows and macOS.

CVSS Score: 7.8

SEVERITY: Critical

THREAT:
This vulnerability affects Microsoft Office by allowing arbitrary code execution through a specially crafted Office document. An attacker can distribute the malicious file through phishing emails, file-sharing platforms, or other delivery methods and convince a user to open or preview it. Because the Preview Pane is also an attack vector, users may be exposed without fully opening the document. Successful exploitation allows the attacker to execute code with the privileges of the current user.

EXPLOITS:
At the time of publication, the vulnerability has not been publicly disclosed and Microsoft has not detected active exploitation. Microsoft assesses exploitation as less likely. The CVSS v3.1 temporal metrics list exploit code maturity as Unproven, and the provided information does not confirm the existence of publicly available proof-of-concept exploit code.

TECHNICAL SUMMARY:
The vulnerability is caused by a use-after-free (CWE-416) memory management flaw in Microsoft Office. An attacker can craft a malicious Office document that triggers access to memory after it has been freed, resulting in memory corruption and arbitrary code execution. Although Microsoft classifies the issue as a Remote Code Execution vulnerability, the attack itself is executed locally after user interaction. Microsoft also confirms that the Preview Pane is an attack vector, meaning specially crafted documents may trigger the vulnerability during preview.

EXPLOITABILITY:
Affected products include Microsoft 365 Apps for Enterprise (32-bit and 64-bit), Microsoft Office 2016, Microsoft Office 2019, Microsoft Office 365 for Mac, Microsoft Office LTSC 2021, Microsoft Office LTSC 2024, Microsoft Office LTSC for Mac 2021, and Microsoft Office LTSC for Mac 2024. Exploitation requires no attacker privileges but does require user interaction, specifically opening or previewing a specially crafted Office document.

BUSINESS IMPACT:
Microsoft Office remains one of the primary entry points for phishing and malware campaigns. Successful exploitation could allow attackers to execute malicious code, install ransomware, steal sensitive business information, establish persistence on endpoints, or use compromised systems as a foothold for further attacks. Organizations that frequently exchange Office documents with external users should prioritize remediation.

WORKAROUND:
No mitigations or workarounds are available. Microsoft recommends installing the appropriate security updates for all affected Microsoft Office products.

URGENCY:
This vulnerability should be deployed urgently because it is rated Critical and affects one of the most widely used productivity platforms in enterprise environments. Although Microsoft has not observed active exploitation and rates exploitation as less likely, Office documents remain a common delivery mechanism for cyberattacks. Prompt installation of security updates significantly reduces the risk of document-based compromise.