CVE-2025-2146: Canon Satera MF656Cdw Buffer Overflow Flaw

CVE-2025-2146 Overview

CVE-2025-2146 is a critical buffer overflow vulnerability affecting the WebService Authentication processing component in Canon Small Office Multifunction Printers and Laser Printers. This vulnerability allows an attacker on the same network segment to cause the affected device to become unresponsive or execute arbitrary code. The flaw affects firmware version v05.07 and earlier across multiple Canon product lines sold in Japan, the United States, and Europe.

Critical Impact

Network-adjacent attackers can exploit this buffer overflow to achieve remote code execution or denial of service on vulnerable Canon printers without requiring authentication or user interaction.

Affected Products

• Canon Satera Series (Japan): MF656Cdw, MF654Cdw, MF551dw, MF457dw - firmware v05.07 and earlier
• Canon Color imageCLASS/imageCLASS Series (US): MF656Cdw, MF654Cdw, MF653Cdw, MF652Cdw, LBP633Cdw, LBP632Cdw, MF455dw, MF453dw, MF452dw, MF451dw, LBP237dw, LBP236dw, X MF1238 II, X MF1643i II, X MF1643iF II, X LBP1238 II - firmware v05.07 and earlier
• Canon i-SENSYS/imageRUNNER Series (Europe): MF657Cdw, MF655Cdw, MF651Cdw, LBP633Cdw, LBP631Cdw, MF553dw, MF552dw, MF455dw, MF453dw, LBP236dw, LBP233dw, 1643iF II, 1643i II, X 1238iF II, X 1238i II, X 1238P II, X 1238Pr II - firmware v05.07 and earlier

Discovery Timeline

• 2025-05-26 - CVE-2025-2146 published to NVD
• 2025-06-03 - Last updated in NVD database

Technical Details for CVE-2025-2146

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption flaw that occurs when the WebService Authentication processing module fails to properly validate input boundaries. When processing authentication requests via WebService protocols, the affected firmware does not adequately check the size of incoming data before copying it into a fixed-size buffer, leading to a classic buffer overflow condition.

The vulnerability is exploitable over the network without requiring any privileges or user interaction. An attacker positioned on the same network segment as the vulnerable printer can craft malicious authentication requests that overflow the buffer, potentially corrupting adjacent memory regions. This memory corruption can be leveraged to crash the device (denial of service) or, more critically, to hijack program execution flow and achieve arbitrary code execution on the printer's embedded system.

Root Cause

The root cause is improper input validation in the WebService Authentication processing code. The firmware fails to enforce proper boundary checks when handling authentication-related data, allowing oversized input to overflow allocated buffer space. This represents a fundamental secure coding failure where user-controlled data is processed without adequate length validation before memory operations.

Attack Vector

The attack vector is network-based, requiring the attacker to have access to the same network segment as the vulnerable printer. The attack can be executed remotely without authentication and does not require any user interaction, making it particularly dangerous in enterprise environments where printers are often deployed on internal networks with minimal security controls.

An attacker would craft a malicious WebService authentication request containing oversized data designed to overflow the vulnerable buffer. When the printer processes this request, the buffer overflow occurs, potentially allowing the attacker to overwrite critical memory structures such as return addresses or function pointers, ultimately achieving code execution with the privileges of the printer's firmware.

Detection Methods for CVE-2025-2146

Indicators of Compromise

• Unexpected printer crashes, reboots, or unresponsive states without apparent cause
• Anomalous network traffic patterns targeting printer WebService ports
• Unusual authentication attempts or malformed requests in printer logs if accessible
• Printers exhibiting unexpected behavior such as unauthorized configuration changes

Detection Strategies

• Monitor network traffic for abnormally large authentication requests directed at Canon printers
• Implement network intrusion detection rules to identify potential buffer overflow attack patterns targeting printer services
• Deploy network segmentation to isolate printers and enable focused traffic analysis
• Use vulnerability scanning tools to identify printers running vulnerable firmware versions (v05.07 and earlier)

Monitoring Recommendations

• Enable logging on network devices to capture traffic to and from printer IP addresses
• Configure alerts for printer service crashes or unexpected restarts
• Regularly audit printer firmware versions against the list of affected products
• Monitor for scanning activity targeting common printer ports and WebService endpoints

How to Mitigate CVE-2025-2146

Immediate Actions Required

• Identify all Canon printers in your environment running affected firmware versions (v05.07 and earlier)
• Prioritize network segmentation to isolate vulnerable printers from untrusted network segments
• Restrict network access to printer WebService interfaces using firewall rules or ACLs
• Apply firmware updates as soon as they become available from Canon

Patch Information

Canon has acknowledged this vulnerability and released security advisories. Organizations should consult the official Canon security resources for firmware updates:

• Canon Vulnerability Response (Japan)
• Canon PSIRT Advisory CP2025-001
• Canon Europe Product Security News
• Canon USA Service Notice

Firmware updates should be applied to all affected devices as the primary remediation measure.

Workarounds

• Place affected printers on isolated network segments with restricted access from general user networks
• Implement strict firewall rules to block external and unauthorized internal access to printer WebService ports
• Disable unnecessary network services on the printer if possible through the device configuration
• Consider temporarily taking vulnerable printers offline in high-security environments until patches can be applied

# Example network segmentation using iptables
# Restrict access to printer subnet from specific management hosts only
iptables -A FORWARD -d 192.168.10.0/24 -s 192.168.1.100 -j ACCEPT
iptables -A FORWARD -d 192.168.10.0/24 -j DROP