CVE-2024-12649: Canon Printer Buffer Overflow Vulnerability

CVE-2024-12649 Overview

CVE-2024-12649 is a critical buffer overflow vulnerability affecting the XPS data font processing functionality in Canon Small Office Multifunction Printers and Laser Printers. This vulnerability allows an attacker positioned on the same network segment to send specially crafted XPS print data that triggers a buffer overflow condition, potentially causing the affected device to become unresponsive or enabling arbitrary code execution on the printer firmware.

The vulnerability stems from improper bounds checking during the processing of font data within XPS (XML Paper Specification) documents. When a malicious XPS file containing specially crafted font data is processed by vulnerable Canon printers, the firmware fails to properly validate the size of incoming data before writing it to memory buffers, resulting in a classic buffer overflow condition.

Critical Impact

Network-accessible Canon printers running firmware v05.04 or earlier are vulnerable to remote code execution without authentication, potentially allowing attackers to gain persistent access to network infrastructure through compromised printing devices.

Affected Products

• Canon Satera MF656Cdw/MF654Cdw (Japan) - firmware v05.04 and earlier
• Canon Color imageCLASS MF656Cdw/MF654Cdw/MF653Cdw/MF652Cdw/LBP633Cdw/LBP632Cdw (US) - firmware v05.04 and earlier
• Canon i-SENSYS MF657Cdw/MF655Cdw/MF651Cdw/LBP633Cdw/LBP631Cdw (Europe) - firmware v05.04 and earlier
• Canon MF455dw/MF453dw/MF452dw/MF451dw/MF465dw/MF462dw series
• Canon LBP237dw/LBP236dw/LBP247dw/LBP246dw series
• Canon MF1238 II/MF1440/MF1643if II/MF1643i II series
• Canon LBP1238 II/LBP1440 series

Discovery Timeline

• 2025-01-28 - CVE-2024-12649 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2024-12649

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption flaw that occurs when the printer firmware writes data past the boundaries of an allocated buffer during XPS font data processing. The attack can be executed remotely over the network without requiring any authentication or user interaction, making it particularly dangerous in enterprise environments where printers are often overlooked in security monitoring.

The XPS document format includes embedded font resources that are parsed by the printer's rendering engine. The vulnerable code path fails to properly validate the size parameters associated with font data structures before copying content into fixed-size memory buffers. An attacker can craft an XPS document with malformed font metadata that specifies larger data sizes than expected, causing the parser to write beyond allocated memory boundaries.

Successful exploitation could allow an attacker to corrupt adjacent memory structures, potentially hijacking control flow to execute arbitrary code with the privileges of the printer firmware. This could enable persistent backdoor installation, network reconnaissance from the printer's network position, or use of the compromised device as a pivot point for lateral movement within the organization.

Root Cause

The root cause of CVE-2024-12649 is insufficient input validation in the XPS font parsing routines within the Canon printer firmware. Specifically, the firmware does not properly verify that the declared size of font data structures matches the actual available buffer space before performing memory copy operations. This allows an attacker to trigger an out-of-bounds write by supplying font data with manipulated size fields that exceed the buffer's capacity.

The vulnerability exists because the font processing code trusts size values embedded in the XPS document without enforcing proper bounds checking, a common oversight in embedded systems where memory constraints often lead to fixed-size buffer allocations.

Attack Vector

The attack vector for this vulnerability is network-based, requiring the attacker to be on the same network segment as the vulnerable printer. The attack does not require any authentication credentials or user interaction. An attacker can exploit this vulnerability by:

1. Identifying vulnerable Canon printers on the network through service discovery
2. Crafting a malicious XPS document containing specially formatted font data with oversized length fields
3. Sending the XPS document to the printer via standard printing protocols (such as IPP, LPR, or SMB print sharing)
4. The printer processes the malicious XPS data, triggering the buffer overflow during font parsing
5. Depending on the attacker's payload, this results in either denial of service (printer crash/hang) or arbitrary code execution

The attack surface is significant in environments where printers are directly accessible on the corporate network without proper segmentation.

Detection Methods for CVE-2024-12649

Indicators of Compromise

• Unexpected printer crashes, reboots, or unresponsive states following print job submissions
• Unusual network traffic patterns originating from Canon printers, especially outbound connections to unexpected destinations
• Modified printer configuration settings or unexpected firmware changes
• Anomalous XPS print jobs in printer logs, particularly those with unusually large or malformed font data
• Network scanning activity originating from printer IP addresses

Detection Strategies

• Monitor network traffic to/from Canon printers for unusual patterns, particularly large XPS print jobs or unexpected outbound connections
• Implement network intrusion detection signatures to identify malformed XPS documents targeting font processing routines
• Enable verbose logging on print servers to capture details about submitted print jobs and their sources
• Deploy endpoint detection on systems that submit print jobs to identify potentially malicious XPS document generation

Monitoring Recommendations

• Segment printers onto dedicated VLANs with restricted network access and monitor inter-VLAN traffic for anomalies
• Implement regular firmware version auditing across all Canon printers to ensure vulnerable versions are identified
• Configure alerting for printer state changes including unexpected reboots or configuration modifications
• Monitor for unusual authentication attempts or configuration access to printer management interfaces

How to Mitigate CVE-2024-12649

Immediate Actions Required

• Update firmware on all affected Canon printers to versions newer than v05.04 immediately
• Isolate vulnerable printers on a segmented network VLAN with restricted access until patching is complete
• Disable direct internet access for all printing devices
• Review and restrict which systems can submit print jobs to affected printers
• Disable XPS printing functionality if not required for business operations

Patch Information

Canon has released firmware updates to address this vulnerability. Organizations should obtain the latest firmware from official Canon support channels. For detailed patch information and download links, refer to the official Canon security advisories:

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

Workarounds

• Implement network segmentation to isolate printers from general user networks and restrict access to authorized print servers only
• Disable XPS printing support on affected devices if this functionality is not required
• Configure firewall rules to limit which IP addresses can communicate with printers on printing ports
• Enable access control lists on network switches to restrict printer accessibility to authorized systems
• Consider implementing a print server architecture where direct network access to printers is not required

# Example network segmentation using iptables on a print server
# Restrict printer access to only the print server
iptables -A FORWARD -d 192.168.10.0/24 -p tcp --dport 9100 -j DROP
iptables -A FORWARD -s 192.168.1.100 -d 192.168.10.0/24 -p tcp --dport 9100 -j ACCEPT

# Block outbound internet access from printer VLAN
iptables -A FORWARD -s 192.168.10.0/24 -d 0.0.0.0/0 -j DROP
iptables -A FORWARD -s 192.168.10.0/24 -d 192.168.0.0/16 -j ACCEPT