CVE-2025-55310 is a security vulnerability identified in Foxit PDF and Editor software for Windows and macOS platforms, affecting versions prior to 13.2 and 2025 prior to 2025.2. The vulnerability arises from the StartPage feature, which relies on static HTML files to display content upon application startup. An attacker who can modify or replace these static HTML files can manipulate the application to load malicious or compromised content when it launches. This attack vector can result in unauthorized disclosure of sensitive information, unauthorized data access, or other security impacts depending on the malicious payload delivered through the compromised HTML content. The exploitation requires the attacker to have the capability to alter local files used by the application, which implies either prior local system compromise, malicious insider activity, or a supply chain attack that replaces legitimate files with malicious ones. The vulnerability does not require user interaction beyond starting the application, but it does require write access to the affected files. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The absence of patches at the time of disclosure suggests that users should be vigilant and implement interim mitigations. This vulnerability highlights the risks associated with local file integrity and the trust placed in static content loaded by applications during startup.

For European organizations, the impact of CVE-2025-55310 can be significant, especially for those relying heavily on Foxit PDF and Editor for document management and processing. Successful exploitation could lead to unauthorized access to sensitive documents, leakage of confidential information, and potential lateral movement within networks if attackers gain footholds through compromised endpoints. This is particularly concerning for sectors such as finance, legal, healthcare, and government agencies where document confidentiality is paramount. The vulnerability could also undermine trust in document workflows and increase the risk of data breaches. Since the attack requires local file modification, organizations with weak endpoint security or insufficient file integrity monitoring are at higher risk. The lack of known exploits in the wild currently reduces immediate threat levels but does not eliminate the risk of future exploitation. Additionally, the potential for supply chain attacks targeting the distribution or update mechanisms of Foxit software could amplify the impact across multiple organizations.

To mitigate CVE-2025-55310, European organizations should implement the following specific measures: 1) Restrict write permissions on directories and files associated with the Foxit PDF and Editor StartPage feature to trusted administrators only, preventing unauthorized modification of static HTML files. 2) Employ file integrity monitoring solutions to detect unauthorized changes to application files and trigger alerts for investigation. 3) Enforce endpoint security best practices, including regular patching of operating systems and applications, to reduce the risk of local compromise. 4) Use application whitelisting to prevent unauthorized executables or scripts from running on endpoints. 5) Monitor for unusual application behavior or network activity that could indicate exploitation attempts. 6) Once patches or updates become available from Foxit, prioritize their deployment across all affected systems. 7) Educate users about the risks of running untrusted software and the importance of reporting suspicious activity. 8) Review and secure software supply chain processes to detect and prevent tampering with application files during distribution or updates.