CVE-2025-66495 is a use-after-free vulnerability classified under CWE-416 found in Foxit PDF Reader's annotation handling module. This vulnerability affects multiple versions of Foxit PDF Reader on Windows and MacOS platforms, specifically versions 2025.2.1 and earlier, 14.0.1 and earlier, and 13.2.1 and earlier. The flaw arises when the application processes a PDF file containing maliciously crafted JavaScript code embedded within annotations. The vulnerability occurs because the software accesses or dereferences a pointer to memory that has already been freed, leading to undefined behavior. This memory corruption can be exploited by a remote attacker to execute arbitrary code on the victim's machine. The attack vector requires the victim to open a malicious PDF file, thus necessitating user interaction but no prior authentication or elevated privileges. The CVSS v3.1 base score is 7.8, indicating high severity, with metrics showing low attack complexity, no privileges required, but user interaction needed. The impact on confidentiality, integrity, and availability is high, as arbitrary code execution could allow full system compromise. No public exploits or patches are currently available, but the vulnerability is publicly disclosed and should be addressed promptly. The flaw highlights the risks associated with processing complex PDF features like JavaScript and annotations, which are often overlooked in security assessments.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Foxit PDF Reader in corporate, governmental, and critical infrastructure environments. Successful exploitation could lead to remote code execution, enabling attackers to steal sensitive data, disrupt operations, or establish persistent footholds within networks. Sectors such as finance, healthcare, legal, and public administration, which frequently handle PDF documents, are particularly vulnerable. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to deliver malicious PDFs. Given the high confidentiality, integrity, and availability impact, exploitation could result in data breaches, ransomware deployment, or espionage activities. The lack of known exploits currently provides a window for proactive mitigation, but the public disclosure increases the risk of future weaponization. European organizations with lax PDF handling policies or outdated Foxit Reader installations face elevated exposure. The threat also underscores the importance of endpoint security controls and user awareness training in mitigating such risks.

1. Immediately inventory and identify all instances of Foxit PDF Reader in use across the organization, including version numbers and operating systems. 2. Monitor Foxit Software's official channels for patches or updates addressing CVE-2025-66495 and apply them as soon as they become available. 3. Until patches are released, consider temporarily restricting or disabling the use of Foxit PDF Reader for opening untrusted or external PDF files. 4. Implement strict email filtering and attachment scanning to detect and block potentially malicious PDFs containing JavaScript. 5. Employ endpoint protection solutions capable of detecting anomalous behavior related to memory corruption or code execution attempts originating from PDF readers. 6. Educate users about the risks of opening unsolicited or suspicious PDF attachments, emphasizing the need for caution with documents from unknown sources. 7. Where feasible, use sandboxing or isolated environments for opening PDFs from untrusted origins to contain potential exploitation. 8. Review and harden PDF reader configurations to disable or limit JavaScript execution within PDFs if the feature is not essential for business processes. 9. Maintain robust backup and incident response plans to quickly recover from potential compromises stemming from exploitation of this vulnerability.