CVE-2024-47939 Overview
CVE-2024-47939 is a stack-based buffer overflow [CWE-121] affecting multiple laser printers and multifunction printers (MFPs) that implement the Ricoh Web Image Monitor interface. An unauthenticated attacker can send a specially crafted request over the network to trigger the overflow. Successful exploitation may result in arbitrary code execution or a denial-of-service (DoS) condition on the affected device.
The issue also impacts certain Konica Minolta devices that incorporate the same Ricoh Web Image Monitor component, expanding the vulnerable device footprint across enterprise print fleets.
Critical Impact
Remote, unauthenticated attackers may achieve arbitrary code execution or crash the device by sending a malformed request to Ricoh Web Image Monitor.
Affected Products
- Multiple Ricoh laser printers and MFPs implementing Web Image Monitor
- Konica Minolta devices incorporating the affected Ricoh Web Image Monitor component
- Refer to the Ricoh Vulnerability Advisory and Konica Minolta Security Notice for the full list of affected models and firmware versions
Discovery Timeline
- 2024-11-01 - CVE-2024-47939 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-47939
Vulnerability Analysis
The flaw resides in the Web Image Monitor component, a web-based administrative interface embedded in Ricoh laser printers and MFPs. The interface fails to validate the length of attacker-controlled input before copying it onto a fixed-size stack buffer. When a crafted HTTP request exceeds the expected size, adjacent stack memory including the saved return address is overwritten.
Because Web Image Monitor is typically exposed on the local network without authentication for many management endpoints, the exposure surface is broad. Successful exploitation grants execution in the context of the printer's embedded firmware process. At minimum, the corruption causes the device to crash and require a reboot.
The JVN report JVN87770340 and Ricoh coordinated advisory confirm the same root cause across the affected product families.
Root Cause
The root cause is missing bounds checking on data written to a stack-allocated buffer during HTTP request parsing in Web Image Monitor. The condition maps directly to [CWE-121: Stack-based Buffer Overflow]. Attack complexity is elevated because the exploit depends on device model, firmware layout, and memory protections present on the embedded system.
Attack Vector
The attack vector is network-based. An attacker with reachability to the printer's HTTP or HTTPS management interface sends a specially crafted request to a vulnerable Web Image Monitor endpoint. No authentication and no user interaction are required. Enterprise deployments that expose printer management interfaces to broad internal VLANs or, worse, to the internet, face the highest risk.
No verified public proof-of-concept code examples are available at time of writing. Refer to the vendor advisories for technical details.
Detection Methods for CVE-2024-47939
Indicators of Compromise
- Unexpected reboots, service restarts, or watchdog resets on Ricoh or Konica Minolta MFPs
- Malformed or oversized HTTP requests targeting Web Image Monitor URIs in network capture or proxy logs
- Outbound connections from printer management interfaces to unfamiliar IP addresses after a suspicious HTTP request
- New or modified administrative accounts on the printer's Web Image Monitor console
Detection Strategies
- Inspect HTTP and HTTPS traffic destined for printer IP ranges for abnormally long header fields, URIs, or POST bodies
- Correlate printer device crashes with preceding inbound network requests using SIEM search across syslog and network telemetry
- Deploy IDS or IPS signatures that flag oversized parameters targeting Ricoh Web Image Monitor endpoints
Monitoring Recommendations
- Enable and forward printer syslog to a centralized logging platform for correlation with network events
- Baseline normal Web Image Monitor request sizes and alert on outliers
- Monitor for administrative interface access originating from user workstation subnets that would not normally manage printers
How to Mitigate CVE-2024-47939
Immediate Actions Required
- Inventory all Ricoh and Konica Minolta laser printers and MFPs and cross-reference firmware versions against the vendor advisories
- Restrict access to Web Image Monitor to a dedicated management VLAN or trusted administrator hosts using firewall or ACL rules
- Verify no affected devices are exposed to the public internet using external attack surface scans
- Apply vendor-supplied firmware updates as soon as they are available for your specific model
Patch Information
Ricoh has published fixed firmware for affected models. Consult the Ricoh Vulnerability Advisory (ricoh-2024-000011) and the Ricoh Japan advisory for the model-to-firmware mapping. Konica Minolta customers should follow guidance in the Konica Minolta Security Notice.
Workarounds
- Disable Web Image Monitor on devices where it is not required for daily operations
- Place all printers behind a network segment that blocks inbound HTTP and HTTPS from user and guest networks
- Enforce administrative authentication on all management endpoints and change default credentials
- Where supported, restrict Web Image Monitor access by source IP address in the printer's own access control settings
# Example: Restrict printer management access with iptables on an upstream Linux gateway
# Allow only the admin subnet (10.10.50.0/24) to reach printer VLAN (10.20.30.0/24) on HTTP/HTTPS
iptables -A FORWARD -s 10.10.50.0/24 -d 10.20.30.0/24 -p tcp -m multiport --dports 80,443 -j ACCEPT
iptables -A FORWARD -d 10.20.30.0/24 -p tcp -m multiport --dports 80,443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
