CVE-2025-20265 is a critical vulnerability in Cisco Secure Firewall Management Center (FMC) software versions 7.0.7 and 7.7.0, specifically in the RADIUS subsystem implementation. The flaw stems from improper neutralization of special elements in user input during the authentication phase, allowing an unauthenticated remote attacker to inject arbitrary shell commands. The vulnerability is exploitable when FMC is configured to use RADIUS authentication for its web-based management interface or SSH management access. An attacker can send crafted input as part of the authentication credentials, which the vulnerable RADIUS subsystem fails to sanitize properly, leading to command injection executed with high privileges on the device. This can result in full compromise of the FMC, enabling attackers to manipulate firewall policies, intercept or redirect traffic, disable security controls, or pivot into the protected network. The vulnerability has a CVSS v3.1 base score of 10.0, reflecting its criticality with network attack vector, no required privileges or user interaction, and complete impact on confidentiality, integrity, and availability. Although no public exploits have been reported yet, the ease of exploitation and potential impact make this a significant threat. Cisco Firepower Management Center is widely used in enterprise and service provider environments to manage firewall and intrusion prevention systems, making this vulnerability a high-value target for attackers. The vulnerability was published on August 14, 2025, and Cisco has not yet provided official patches or mitigations, increasing the urgency for organizations to implement interim controls.

For European organizations, the impact of CVE-2025-20265 is severe. Successful exploitation can lead to complete compromise of the Cisco FMC device, which centrally manages firewall policies and security controls. This can result in unauthorized access to sensitive network segments, interception or manipulation of network traffic, disruption of security monitoring, and potential lateral movement within the network. Critical infrastructure operators, financial institutions, government agencies, and large enterprises relying on Cisco FMC for perimeter defense and network segmentation are at heightened risk. The loss of confidentiality, integrity, and availability of security management functions can cause significant operational disruption, data breaches, and regulatory non-compliance under GDPR and other European cybersecurity regulations. Given the critical role of FMC in network security, exploitation could facilitate large-scale cyberattacks or espionage campaigns targeting European entities. The vulnerability’s remote, unauthenticated nature and lack of required user interaction further increase the risk of widespread exploitation if not mitigated promptly.

1. Immediately assess whether Cisco FMC instances are configured to use RADIUS authentication for web or SSH management interfaces. If possible, disable RADIUS authentication temporarily until patches are available. 2. Restrict management interface access using network segmentation, firewall rules, and VPNs to limit exposure to trusted administrators only. 3. Monitor authentication logs for unusual or malformed RADIUS authentication attempts that may indicate exploitation attempts. 4. Implement strict input validation and filtering at network boundaries where possible to detect and block suspicious payloads targeting RADIUS authentication. 5. Apply Cisco’s official patches or updates as soon as they are released. 6. If patches are unavailable, consider deploying compensating controls such as multi-factor authentication for management access and enhanced network monitoring. 7. Conduct regular security audits and penetration testing focused on management interfaces to identify potential exploitation vectors. 8. Educate security teams about this vulnerability and ensure incident response plans include procedures for detecting and responding to FMC compromises.