CVE-2025-66494 is a use-after-free vulnerability classified under CWE-416 affecting Foxit PDF Reader on Windows platforms. The vulnerability exists in the PDF file parsing logic where a PDF object that is referenced by multiple parent objects can be prematurely freed while still being accessed. This memory management flaw can lead to arbitrary code execution by a remote attacker who crafts a malicious PDF file and convinces a user to open it. The vulnerability affects multiple versions of Foxit PDF Reader, including 2025.2.1 and earlier, 14.0.1 and earlier, and 13.2.1 and earlier. The CVSS v3.1 score is 7.8, indicating high severity, with attack vector local (requiring user interaction), low attack complexity, no privileges required, and user interaction necessary. The impact includes full compromise of confidentiality, integrity, and availability of the affected system. Although no known exploits are currently reported in the wild, the nature of the vulnerability and widespread use of Foxit PDF Reader make it a significant risk. The vulnerability was publicly disclosed on December 19, 2025, but no official patches or mitigation tools have been linked yet. Organizations relying on Foxit PDF Reader should prepare for imminent patching and consider interim mitigations to reduce exposure.

For European organizations, this vulnerability poses a substantial risk due to the widespread use of Foxit PDF Reader in business, government, and critical infrastructure sectors. Successful exploitation can lead to remote code execution, allowing attackers to gain unauthorized access, steal sensitive data, disrupt operations, or deploy ransomware. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to deliver malicious PDFs. Confidentiality breaches could expose personal data protected under GDPR, leading to regulatory penalties and reputational damage. Integrity and availability impacts could disrupt business continuity and critical services. The high CVSS score reflects the potential for severe operational and financial consequences. Organizations in finance, healthcare, legal, and public administration are particularly vulnerable due to their reliance on PDF documents and regulatory compliance requirements.

1. Immediately restrict the opening of PDF files from untrusted or unknown sources through email filtering and endpoint controls. 2. Employ application whitelisting to limit execution of unauthorized code spawned by malicious PDFs. 3. Use sandboxing or isolated environments for opening PDF files, especially those from external sources. 4. Monitor endpoint behavior for unusual process activity or memory anomalies indicative of exploitation attempts. 5. Educate users on the risks of opening unsolicited PDF attachments and implement phishing awareness training. 6. Prepare for rapid deployment of official patches from Foxit Software once available, and test updates in controlled environments before widespread rollout. 7. Consider alternative PDF readers with a stronger security track record as a temporary measure. 8. Implement network segmentation to limit lateral movement if a system is compromised. 9. Maintain up-to-date backups to enable recovery in case of ransomware or destructive attacks stemming from exploitation.