CVE-2025-62553 is a use-after-free vulnerability classified under CWE-416 affecting Microsoft Office Excel 2019, specifically version 19.0.0. This vulnerability occurs when Excel improperly manages memory, freeing an object while it is still in use, which can lead to arbitrary code execution. An attacker can exploit this flaw by convincing a user to open a maliciously crafted Excel file, triggering the use-after-free condition. The vulnerability requires local execution with user interaction (opening the file) but does not require prior authentication or elevated privileges. The CVSS v3.1 score of 7.8 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no public exploits have been reported yet, the vulnerability is critical due to the widespread use of Microsoft Office in enterprise environments. The flaw could allow attackers to execute arbitrary code within the context of the logged-in user, potentially leading to full system compromise if the user has administrative rights. The vulnerability is currently published but lacks an official patch, so organizations must rely on interim mitigations until Microsoft releases an update. The vulnerability's exploitation vector is local, but the common vector is social engineering via malicious Excel documents delivered through email or other file-sharing methods.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Microsoft Office 2019 across public and private sectors. Successful exploitation could lead to unauthorized code execution, enabling attackers to steal sensitive data, install malware, or disrupt business operations. Critical sectors such as finance, healthcare, government, and energy, which heavily rely on Office productivity tools, could face severe operational and reputational damage. The vulnerability affects confidentiality, integrity, and availability of systems, potentially allowing lateral movement within networks if attackers escalate privileges. Given the requirement for user interaction, phishing campaigns targeting European employees could be an effective attack vector. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as threat actors often develop exploits rapidly after vulnerability disclosure. Organizations with limited patch management capabilities or legacy systems are particularly vulnerable.

1. Implement strict email filtering and attachment scanning to block or quarantine suspicious Excel files, especially from unknown or untrusted sources. 2. Educate users about the risks of opening unsolicited or unexpected Excel attachments and encourage verification before opening. 3. Employ application whitelisting or allowlisting to restrict execution of unauthorized code and scripts within Office applications. 4. Use Microsoft Office Protected View and disable macros by default to reduce attack surface. 5. Monitor endpoint behavior for unusual activity related to Excel processes, such as unexpected child processes or network connections. 6. Segment networks to limit lateral movement if a compromise occurs. 7. Prepare for rapid deployment of patches once Microsoft releases an official fix for this vulnerability. 8. Consider deploying endpoint detection and response (EDR) solutions capable of detecting exploitation attempts of use-after-free vulnerabilities. 9. Regularly back up critical data and verify recovery procedures to mitigate potential ransomware or destructive attacks leveraging this vulnerability.