CVE-2025-67084 is a critical vulnerability affecting InvoicePlane, an open-source invoicing and billing software, specifically versions through 1.6.3. The flaw lies in the file upload functionality for attachments, where authenticated users can upload arbitrary PHP files without sufficient validation or sanitization. This allows attackers to place malicious PHP scripts on the server, which can be executed remotely to gain full control over the affected system. The vulnerability is classified under CWE-616 (Improper Restriction of a File Upload to a Specific Type) and has a CVSS v3.1 base score of 9.9, reflecting its high impact and ease of exploitation. The attack vector is network-based, requiring low attack complexity and only authenticated privileges, with no user interaction needed. The scope is changed, meaning the vulnerability can affect components beyond the initially compromised system, potentially allowing attackers to pivot within the network. Although no public exploits have been reported yet, the critical nature of this vulnerability and the widespread use of InvoicePlane in small and medium enterprises (SMEs) make it a significant threat. The lack of an official patch at the time of disclosure necessitates immediate mitigation through configuration and monitoring. This vulnerability can lead to complete compromise of the invoicing server, exposing sensitive financial data and enabling further attacks on the internal network.

For European organizations, the impact of CVE-2025-67084 is substantial. InvoicePlane is widely used by SMEs across Europe for managing invoicing and billing, making these organizations prime targets. Successful exploitation results in Remote Code Execution, allowing attackers to execute arbitrary commands with the privileges of the web server user. This can lead to data theft, manipulation of financial records, disruption of business operations, and potential lateral movement within corporate networks. Confidentiality is severely impacted as sensitive financial and client data can be exfiltrated. Integrity is compromised through unauthorized modification of invoices and records, potentially causing financial losses and regulatory non-compliance. Availability is also at risk if attackers deploy ransomware or disrupt services. The requirement for authentication reduces the attack surface but does not eliminate risk, especially if credential theft or weak authentication mechanisms exist. The vulnerability's critical severity and network accessibility make it a high-priority threat for European businesses relying on InvoicePlane.

To mitigate CVE-2025-67084, European organizations should implement the following specific measures: 1) Immediately restrict file upload functionality by enforcing strict file type validation and blocking executable file extensions such as .php, .phtml, and other script types at both application and web server levels. 2) Harden authentication mechanisms by enforcing strong password policies, multi-factor authentication (MFA), and monitoring for suspicious login attempts to reduce the risk of credential compromise. 3) Isolate the InvoicePlane application within a segmented network zone with limited access to critical internal systems to contain potential breaches. 4) Monitor upload directories and web server logs for unusual file uploads or execution attempts, employing file integrity monitoring solutions. 5) Disable execution permissions on directories used for file uploads to prevent execution of uploaded scripts. 6) Regularly back up invoicing data and test restoration procedures to minimize downtime in case of compromise. 7) Stay alert for official patches or updates from InvoicePlane and apply them promptly once available. 8) Conduct security awareness training for users with upload privileges to recognize and prevent misuse. These targeted actions go beyond generic advice and address the specific attack vectors and exploitation methods of this vulnerability.