CVE-2025-53869 identifies a security vulnerability in multiple multifunction printers (MFPs) manufactured by Brother Industries, Ltd. The core issue lies in improper validation of server certificates by these devices. Specifically, the MFPs fail to correctly verify the authenticity of server certificates during secure communications, which can be exploited by a man-in-the-middle (MitM) attacker. By leveraging this flaw, an attacker positioned on the network path can replace the device’s trusted root certificate store with a set of arbitrary certificates under their control. This manipulation undermines the device’s trust model, potentially allowing interception or alteration of encrypted communications between the MFP and other network services. The vulnerability does not directly compromise confidentiality or availability but impacts integrity by enabling unauthorized certificate replacement. The CVSS 3.1 base score is 3.7, reflecting a low severity rating primarily due to the high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), and no impact on confidentiality or availability. The scope remains unchanged (S:U). No known exploits have been reported in the wild, and affected versions are to be confirmed via vendor advisories. This vulnerability highlights the importance of robust certificate validation in embedded network devices, especially those handling sensitive documents and communications.

For European organizations, the primary impact of CVE-2025-53869 is the potential compromise of the integrity of communications involving Brother MFP devices. Since these devices are often integrated into enterprise networks for scanning, printing, and document management, an attacker exploiting this vulnerability could intercept or manipulate data transmitted to or from the MFPs. Although confidentiality and availability are not directly affected, the ability to replace trusted root certificates could facilitate further attacks such as credential theft or injection of malicious content in document workflows. Sectors such as government, finance, healthcare, and legal services, which rely heavily on secure document handling, may face increased risk. Additionally, the vulnerability could undermine compliance with data protection regulations like GDPR if sensitive information is exposed or altered. The low CVSS score suggests exploitation is complex and less likely, but the potential for stealthy MitM attacks in internal networks remains a concern.

1. Monitor Brother Industries’ official security advisories and apply firmware updates or patches promptly once released to address CVE-2025-53869. 2. Restrict network access to MFP management interfaces and services using network segmentation, firewalls, and access control lists to limit exposure to potential attackers. 3. Implement network-level protections such as TLS inspection and anomaly detection to identify suspicious certificate changes or MitM attempts. 4. Use strong network authentication and encryption protocols for all communications involving MFPs. 5. Regularly audit and verify the root certificate stores on MFP devices to detect unauthorized modifications. 6. Educate IT staff on the risks of certificate validation flaws and ensure secure configuration of all networked printers and scanners. 7. Consider deploying endpoint detection and response (EDR) solutions that can monitor unusual device behavior related to certificate stores. 8. Maintain an inventory of all Brother MFP devices in use and their firmware versions to prioritize patching and risk assessment.