CVE-2025-66493 is a use-after-free vulnerability classified under CWE-416, found in the AcroForm JavaScript handling components of Foxit PDF Reader and Foxit PDF Editor on Windows. The flaw exists in versions 2025.2.1 and earlier, 14.0.1 and earlier, and 13.2.1 and earlier. When a user opens a PDF containing specially crafted JavaScript code embedded in AcroForms, the software may access or dereference a pointer to memory that has already been freed. This unsafe memory access can lead to arbitrary code execution by a remote attacker, potentially allowing full system compromise. The vulnerability requires user interaction (opening the malicious PDF) but does not require any prior authentication or elevated privileges. The CVSS v3.1 base score is 7.8, indicating high severity with impacts on confidentiality, integrity, and availability. The attack vector is local (user must open the file), with low attack complexity and no privileges required, but user interaction is necessary. No public exploits or active exploitation campaigns have been reported yet. The vulnerability highlights the risks inherent in processing complex PDF features such as embedded JavaScript, which can be abused to trigger memory corruption bugs. The lack of patch links suggests that fixes may be pending or recently released, so users should monitor vendor advisories closely.

For European organizations, this vulnerability poses a significant risk of remote code execution leading to potential data breaches, system compromise, and disruption of business operations. Since PDFs are widely used for document exchange in corporate, governmental, and financial sectors, attackers could leverage this flaw to deliver malware, ransomware, or conduct espionage. The high impact on confidentiality, integrity, and availability means sensitive information could be exposed or altered, and critical systems could be rendered inoperable. The requirement for user interaction means phishing or social engineering campaigns could be effective attack vectors. Organizations relying on Foxit PDF products for document management, especially those handling sensitive or regulated data, face elevated risks. The vulnerability could also be exploited to establish footholds in networks, facilitating lateral movement and further attacks. The absence of known exploits currently provides a window for proactive mitigation before widespread exploitation occurs.

1. Monitor Foxit Software advisories and promptly apply patches or updates once they become available for the affected versions. 2. Until patches are applied, disable or restrict JavaScript execution within Foxit PDF Reader and Editor settings to reduce attack surface. 3. Implement application whitelisting to prevent unauthorized execution of untrusted PDF files or associated scripts. 4. Employ sandboxing or containerization for PDF readers to isolate potential malicious activity. 5. Educate users to be cautious when opening PDFs from untrusted or unexpected sources, emphasizing phishing awareness. 6. Use email filtering solutions to detect and block malicious PDFs containing suspicious JavaScript. 7. Conduct regular vulnerability assessments and penetration testing focused on document handling workflows. 8. Maintain up-to-date endpoint detection and response (EDR) tools capable of identifying exploitation attempts related to memory corruption. 9. Consider network segmentation to limit the impact of a compromised endpoint. 10. Review and harden security policies around document sharing and handling within the organization.