CVE-2025-55211 is a medium-severity vulnerability classified under CWE-78, which pertains to improper neutralization of special elements used in OS command execution, commonly known as OS Command Injection. This vulnerability affects FreePBX, an open-source web-based graphical user interface widely used for managing telephony systems. Specifically, versions from 17.0.19.11 up to but not including 17.0.21 of the security-reporting module are vulnerable. The flaw allows an authenticated user with access to the Administrator Control Panel (ACP) to execute arbitrary shell commands by maliciously altering the language settings of the framework module. This means that an attacker who has legitimate ACP credentials can inject and run shell commands on the underlying operating system, potentially leading to unauthorized system control or data compromise. The vulnerability does not require user interaction beyond authentication and can be exploited remotely over the network. The issue was addressed and fixed in version 17.0.21 of FreePBX. The CVSS 4.0 base score is 6.3, indicating a medium severity level, with attack vector being network-based, low attack complexity, no user interaction, and requiring privileges (authenticated user). The vulnerability impacts confidentiality, integrity, and availability at a high level due to the ability to execute arbitrary commands with the privileges of the FreePBX process, which could lead to full system compromise if the process runs with elevated rights. No known exploits are currently reported in the wild, but the presence of this vulnerability in a critical telephony management system makes it a significant risk if left unpatched.

For European organizations, the impact of CVE-2025-55211 can be substantial, especially for those relying on FreePBX for their telephony infrastructure. Successful exploitation could allow attackers to gain control over telephony systems, potentially intercepting, redirecting, or disrupting voice communications. This can lead to operational downtime, loss of sensitive communication data, and reputational damage. Given that telephony systems often integrate with other critical business systems, the compromise could serve as a foothold for lateral movement within corporate networks, increasing the risk of broader data breaches or ransomware attacks. Additionally, disruption of telephony services can affect customer support, emergency response, and internal communications, which are critical for many sectors including finance, healthcare, and government institutions prevalent across Europe. The requirement for authenticated access somewhat limits the attack surface but does not eliminate risk, as credential theft or insider threats could facilitate exploitation. The medium severity rating suggests that while the vulnerability is serious, it is not trivially exploitable by unauthenticated attackers, but organizations should prioritize patching to prevent potential exploitation.

To mitigate this vulnerability, European organizations should immediately upgrade FreePBX installations to version 17.0.21 or later, where the issue is resolved. If immediate patching is not feasible, organizations should restrict access to the Administrator Control Panel (ACP) by implementing strong network segmentation and access controls, limiting ACP access to trusted IP addresses only. Enforce multi-factor authentication (MFA) for all ACP users to reduce the risk of credential compromise. Regularly audit and monitor ACP login activity and system logs for unusual or unauthorized actions that could indicate exploitation attempts. Additionally, review and harden the FreePBX configuration to minimize privileges of the FreePBX process and underlying OS user accounts, reducing the potential impact of command injection. Employ intrusion detection systems (IDS) and endpoint detection and response (EDR) solutions to detect anomalous command execution patterns. Finally, conduct regular security awareness training for administrators to recognize phishing or social engineering attempts that could lead to credential theft.