CVE-2025-11155 identifies a weakness in the SATO S86-ex 203dpi printer's web server authentication mechanism. The device transmits user credentials encoded only in base64 within HTTP headers during login requests. Base64 encoding is a reversible encoding scheme rather than encryption, meaning that anyone intercepting the HTTP traffic can decode the credentials without significant effort. The vulnerability is classified under CWE-261, which refers to weak encoding for passwords. The CVSS 4.0 vector indicates the attack requires adjacent network access (AV:A), low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:A). The vulnerability impacts confidentiality highly (VC:H) but does not affect integrity or availability. The scope is limited to the device itself (SC:L). No patches are currently available, and no known exploits have been reported in the wild. This vulnerability primarily threatens environments where network traffic is unencrypted or where attackers can perform man-in-the-middle attacks, such as unsecured Wi-Fi or poorly segmented internal networks. Attackers could gain unauthorized access to the printer's web interface, potentially altering configurations or using the device as a foothold for further network intrusion.

For European organizations, this vulnerability poses a risk of unauthorized access to SATO S86-ex 203dpi printers, which are commonly used in logistics, manufacturing, and retail sectors. Compromise of these devices could lead to exposure of sensitive operational data, disruption of printing services, or use of the printer as a pivot point for lateral movement within corporate networks. Given the medium severity and the requirement for network proximity, the threat is more pronounced in environments with inadequate network segmentation or unencrypted internal traffic. Organizations handling sensitive shipments, product labeling, or inventory management could face operational disruptions or data confidentiality breaches. Additionally, attackers gaining access to the printer’s web interface might modify device settings or firmware, potentially enabling persistent access or further exploitation. The lack of a patch increases the urgency for compensating controls. The impact is heightened in sectors with strict compliance requirements around data protection and operational integrity.

Since no patch is currently available for CVE-2025-11155, European organizations should implement specific mitigations to reduce risk. First, isolate SATO printers on dedicated VLANs or network segments with strict access controls to limit exposure to trusted users and systems only. Employ network monitoring and intrusion detection systems to detect unusual access patterns to printer web interfaces. Where possible, enforce the use of VPNs or encrypted tunnels (e.g., IPsec) for accessing printer management interfaces to prevent interception of HTTP traffic. Disable or restrict web interface access if not required, or configure access control lists to limit management access to specific IP addresses. Educate users about the risks of connecting to unsecured networks where printers are accessible. Regularly audit network configurations and printer settings to detect unauthorized changes. Engage with the vendor for updates or firmware patches and plan for timely deployment once available. Consider replacing affected devices with models supporting secure authentication and encrypted management protocols if risk tolerance is low.