CVE-2025-66494 is a use-after-free vulnerability classified under CWE-416, affecting Foxit PDF Reader on Windows platforms in versions 2025.2.1 and earlier, including 14.0.1 and 13.2.1 and their predecessors. The vulnerability occurs in the PDF file parsing component, where a PDF object that is referenced by multiple parent objects can be prematurely freed while still being accessed. This memory mismanagement can lead to use-after-free conditions, which attackers can exploit to execute arbitrary code remotely. The attack vector involves convincing a user to open a specially crafted malicious PDF file, which triggers the vulnerability during parsing. The CVSS 3.1 score of 7.8 reflects high severity, with attack vector local (AV:L), low attack complexity (AC:L), no privileges required (PR:N), and requiring user interaction (UI:R). The impact includes full compromise of confidentiality, integrity, and availability of the affected system. Although no exploits are currently known in the wild, the vulnerability's nature and Foxit PDF Reader's popularity make it a critical concern. The lack of available patches at the time of publication necessitates immediate mitigation strategies to reduce exposure.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Foxit PDF Reader in both enterprise and government environments for handling PDF documents. Successful exploitation could lead to remote code execution, allowing attackers to gain unauthorized access, steal sensitive data, disrupt operations, or deploy malware such as ransomware. Critical sectors including finance, healthcare, and public administration, which heavily rely on PDF workflows, could face severe operational and reputational damage. The requirement for user interaction (opening a malicious PDF) means phishing campaigns could be an effective attack vector. The vulnerability's ability to compromise confidentiality, integrity, and availability simultaneously elevates the threat level, potentially impacting compliance with GDPR and other data protection regulations. Organizations with limited patch management capabilities or those using legacy versions are particularly vulnerable.

1. Immediately disable JavaScript execution within Foxit PDF Reader to reduce attack surface related to PDF parsing. 2. Employ application sandboxing or containerization to isolate Foxit Reader processes, limiting potential damage from exploitation. 3. Implement strict email filtering and attachment scanning to detect and block malicious PDF files before reaching end users. 4. Educate users on the risks of opening unsolicited or suspicious PDF attachments, emphasizing phishing awareness. 5. Monitor network and endpoint logs for unusual behavior indicative of exploitation attempts. 6. Prepare for rapid deployment of official patches from Foxit Software once released, including testing in controlled environments. 7. Consider alternative PDF readers with a stronger security posture temporarily if patching is delayed. 8. Enforce least privilege principles on user accounts to limit the impact of potential code execution. 9. Regularly back up critical data and verify restoration procedures to mitigate ransomware risks stemming from exploitation.