CVE-2025-14231: Canon Printer Buffer Overflow Vulnerability

CVE-2025-14231 Overview

CVE-2025-14231 is a buffer overflow vulnerability in the Web Services on Devices (WSD) print job processing functionality affecting Canon Small Office Multifunction Printers and Laser Printers. This vulnerability allows an attacker on the same network segment to trigger a denial of service condition (causing the affected product to become unresponsive) or potentially execute arbitrary code on vulnerable devices.

The vulnerability stems from improper bounds checking during WSD print job processing, classified as CWE-787 (Out-of-bounds Write). Given the network-based attack vector requiring no authentication or user interaction, this vulnerability poses significant risk to organizations with affected Canon printers deployed on their networks.

Critical Impact

Network-accessible buffer overflow vulnerability enables remote code execution or denial of service on Canon printers without authentication, potentially allowing attackers to compromise printing infrastructure and pivot within enterprise networks.

Affected Products

• Satera LBP670C Series/Satera MF750C Series firmware v06.02 and earlier (Japan)
• Color imageCLASS LBP630C/Color imageCLASS MF650C Series/imageCLASS LBP230 Series/imageCLASS X LBP1238 II/imageCLASS MF450 Series/imageCLASS X MF1238 II/imageCLASS X MF1643i II/imageCLASS X MF1643iF II firmware v06.02 and earlier (US)
• i-SENSYS LBP630C Series/i-SENSYS MF650C Series/i-SENSYS LBP230 Series/1238P II/1238Pr II/i-SENSYS MF450 Series/i-SENSYS MF550 Series/1238i II/1238iF II/imageRUNNER 1643i II/imageRUNNER 1643iF II firmware v06.02 and earlier (Europe)

Discovery Timeline

• 2026-01-16 - CVE-2025-14231 published to NVD
• 2026-01-16 - Last updated in NVD database

Technical Details for CVE-2025-14231

Vulnerability Analysis

This vulnerability exists in the WSD (Web Services on Devices) protocol implementation within Canon's printer firmware. WSD is a Microsoft-developed protocol that enables automatic discovery and configuration of network-connected devices. The buffer overflow occurs during the processing of print jobs received via WSD, where insufficient bounds checking allows an attacker to write data beyond allocated memory boundaries.

The out-of-bounds write condition (CWE-787) can corrupt adjacent memory regions, potentially overwriting critical data structures or function pointers. This can lead to either a crash condition causing the printer to become unresponsive, or in more severe cases, enable arbitrary code execution if an attacker can precisely control the overflow data.

Since the vulnerability is exploitable over the network without requiring authentication or user interaction, any device on the same network segment as a vulnerable printer can potentially exploit this flaw. This is particularly concerning in enterprise environments where printers are often deployed on shared network segments with minimal security controls.

Root Cause

The root cause is improper input validation and bounds checking in the WSD print job processing code within the Canon printer firmware. When processing incoming WSD print requests, the firmware fails to properly validate the size of certain input data before copying it into fixed-size memory buffers, resulting in a classic buffer overflow condition.

Attack Vector

The attack is network-based, requiring the attacker to have access to the same network segment as the vulnerable printer. The attacker can craft malicious WSD print job requests containing oversized data fields designed to trigger the buffer overflow. Since WSD operates over HTTP/HTTPS (typically on ports 5357/5358), the attack can be delivered via standard network protocols without requiring special access or credentials.

The attack sequence involves:

1. Discovering vulnerable Canon printers on the network via WSD discovery protocols
2. Crafting a malicious WSD print job request with overflow payload
3. Sending the request to the target printer
4. Achieving either denial of service or code execution depending on payload sophistication

No verified exploit code is publicly available for this vulnerability. The vulnerability manifests during WSD print job request parsing where oversized input data exceeds buffer boundaries. See the Canon PSIRT Advisory CP2026-001 for additional technical details.

Detection Methods for CVE-2025-14231

Indicators of Compromise

• Unexpected printer reboots or unresponsive states without clear cause
• Anomalous WSD traffic patterns targeting printer ports 5357/5358
• Unusual network connections originating from printer IP addresses
• Printer firmware modifications or unexpected configuration changes

Detection Strategies

• Monitor network traffic for abnormally large WSD requests targeting Canon printers
• Implement network segmentation alerts for unauthorized access to printer VLANs
• Deploy intrusion detection signatures for WSD protocol anomalies
• Audit printer logs for crash events or service restarts correlated with network activity

Monitoring Recommendations

• Enable logging on network firewalls and IDS/IPS for WSD protocol traffic (ports 5357/5358)
• Implement network behavior analysis to detect unusual printer communication patterns
• Monitor printer availability and response times for potential DoS indicators
• Review SIEM alerts for multiple printer anomalies that may indicate exploitation attempts

How to Mitigate CVE-2025-14231

Immediate Actions Required

• Update affected Canon printer firmware to versions newer than v06.02
• Disable WSD protocol on printers where it is not required for business operations
• Isolate vulnerable printers on dedicated network segments with restricted access
• Implement firewall rules to block WSD traffic (ports 5357/5358) from untrusted network segments

Patch Information

Canon has released security advisories addressing this vulnerability. Organizations should download and apply the latest firmware updates from Canon's official support channels. Firmware updates are available region-specific through:

• Canon Vulnerability Response (Japan)
• Canon PSIRT Advisory CP2026-001
• Canon Europe Product Security
• Canon USA Service Notice

Workarounds

• Disable WSD services on affected printers if the feature is not essential for print operations
• Implement network segmentation to isolate printers from general user networks
• Configure firewall rules to restrict access to printer management interfaces
• Use alternative printing protocols such as IPP or LPD where WSD can be disabled

# Example firewall rule to block WSD traffic to printer subnet
# Adjust IP ranges for your environment
iptables -A FORWARD -p tcp -d 192.168.10.0/24 --dport 5357 -j DROP
iptables -A FORWARD -p tcp -d 192.168.10.0/24 --dport 5358 -j DROP
iptables -A FORWARD -p udp -d 192.168.10.0/24 --dport 3702 -j DROP