CVE-2025-55704: Brother MFPs Information Disclosure Flaw

CVE-2025-55704 Overview

CVE-2025-55704 is a hidden functionality vulnerability affecting multiple multifunction printers (MFPs) manufactured by Brother Industries, Ltd. The flaw allows a remote unauthenticated attacker to retrieve product logs that may contain sensitive information. The issue is classified under [CWE-912: Hidden Functionality], indicating undocumented capabilities present in the firmware that were not intended for end-user or external access. Konica Minolta has also published an advisory, suggesting the affected components extend to OEM-branded devices built on shared Brother firmware.

Critical Impact
Remote attackers can extract device logs over the network without authentication, exposing sensitive operational data and potentially user content metadata.

Affected Products

Multiple Brother Industries, Ltd. multifunction printers (MFPs) — see vendor FAQ for the model list
Konica Minolta OEM MFPs derived from affected Brother firmware
Networked print devices exposing the impacted management interface

Discovery Timeline

2026-01-29 - CVE-2025-55704 published to NVD
2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-55704

Vulnerability Analysis

The vulnerability stems from hidden functionality embedded in the firmware of affected Brother MFPs. An unauthenticated remote attacker can interact with this undocumented feature over the network to obtain device logs. These logs may include sensitive information such as device configuration data, user identifiers, job metadata, network paths, and credentials referenced during normal operation. Because the functionality is undocumented, administrators have no standard configuration option to disable it. The attack requires no privileges and no user interaction, and operates over the network attack vector.

Root Cause

The root cause is the inclusion of undocumented diagnostic or service functionality in production firmware. Hidden features classified under [CWE-912] commonly result from manufacturer debug interfaces, vendor service tools, or OEM integration hooks that remain enabled after release. In this case, the feature exposes log content to network-reachable callers without enforcing authentication or access control.

Attack Vector

Attackers reach the vulnerable functionality across the network by sending crafted requests to the device's management interface. No verified public exploit code is currently available. Technical specifics about the request format, port, and protocol are coordinated through the JVN advisory, the Brother FAQ resource, and the Konica Minolta security advisory. Devices exposed directly to the internet or reachable from untrusted network segments are at the highest risk.

Detection Methods for CVE-2025-55704

Indicators of Compromise

Unexpected inbound connections to MFP management ports from non-administrative hosts or external IP addresses
Repeated requests to undocumented or non-standard URI paths on Brother or Konica Minolta MFP web services
Outbound traffic from print devices to unfamiliar destinations following log-retrieval activity

Detection Strategies

Inventory all Brother and Konica Minolta MFPs and cross-reference firmware versions against the affected list in the vendor advisories
Inspect network flow records for sessions to MFP management interfaces originating outside administrative VLANs
Capture and review HTTP/HTTPS traffic to printer IPs for anomalous endpoint paths consistent with log exfiltration

Monitoring Recommendations

Forward firewall, NetFlow, and DNS logs from network segments hosting MFPs into a centralized analytics platform for long-retention review
Alert on any direct internet exposure of MFP management ports through external attack surface monitoring
Track firmware versions across the print fleet and trigger alerts when devices remain on vulnerable releases beyond the patch window

How to Mitigate CVE-2025-55704

Immediate Actions Required

Identify affected Brother and Konica Minolta MFPs using the model lists in the Brother FAQ and Konica Minolta advisory
Remove MFP management interfaces from internet exposure and restrict access to administrative networks only
Rotate any credentials, SMB shares, LDAP bind accounts, or scan-to-email passwords configured on affected devices, since these may appear in retrieved logs

Patch Information

Brother Industries, Ltd. has published mitigation guidance through its FAQ portal. Refer to the Brother FAQ resource and the JVN advisory JVNVU92878805 for firmware update availability per model. Konica Minolta customers should consult advisory km-2026-0001 for OEM-specific firmware updates.

Workarounds

Place all MFPs on dedicated VLANs with access control lists restricting management traffic to authorized administrator workstations
Disable unused network services and protocols on the device, including legacy management interfaces, where supported by firmware
Apply egress filtering to prevent print devices from initiating outbound connections to untrusted destinations

bash

# Configuration example - restrict MFP management access at the network layer
# Example ACL applied on the switch or firewall facing the printer VLAN
access-list MFP_MGMT permit tcp host 10.10.20.5 10.10.50.0 0.0.0.255 eq 443
access-list MFP_MGMT permit tcp host 10.10.20.5 10.10.50.0 0.0.0.255 eq 80
access-list MFP_MGMT deny   tcp any 10.10.50.0 0.0.0.255 eq 443
access-list MFP_MGMT deny   tcp any 10.10.50.0 0.0.0.255 eq 80
access-list MFP_MGMT permit ip  any any