CVE-2024-28038 is a stack-based buffer overflow vulnerability identified in the web interface of multiple Sharp Corporation multifunction printers (MFPs). The vulnerability occurs due to improper handling of the MFPSESSIONID cookie parameter, where an attacker can supply an excessively long string value that overflows the stack buffer. This overflow can lead to arbitrary code execution on the affected device. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS v3.1 base score is 9.0 (critical), reflecting the vulnerability's potential to compromise confidentiality, integrity, and availability of the device and potentially the broader network. The vulnerability affects multiple Sharp MFP models and versions; specific affected versions are detailed by Sharp Corporation in their advisories. No known exploits have been reported in the wild yet, but the critical nature of the flaw and ease of exploitation make it a high priority for patching. Attackers exploiting this vulnerability could gain control over the printer, intercept or manipulate sensitive documents, disrupt printing services, or use the device as a foothold for lateral movement within a network. The multifunction printers’ role in document processing and network connectivity makes this vulnerability particularly impactful in enterprise and government environments.

For European organizations, the impact of CVE-2024-28038 is significant due to the widespread use of Sharp multifunction printers in offices, government agencies, and critical infrastructure sectors. Successful exploitation could lead to unauthorized access to sensitive documents, disruption of printing and scanning services, and potential network compromise if attackers use the printer as a pivot point. Confidentiality is at risk as attackers might intercept or alter documents processed by the device. Integrity and availability are also threatened, as attackers could execute arbitrary code to disrupt device operation or manipulate data. The vulnerability’s remote exploitability without authentication increases the attack surface, especially for devices exposed to untrusted networks or insufficiently segmented internal networks. European organizations with strict data protection regulations (e.g., GDPR) face additional compliance risks if sensitive information is compromised. The potential for lateral movement within corporate networks elevates the threat to overall organizational cybersecurity posture.

1. Apply official security patches and firmware updates from Sharp Corporation immediately upon release to remediate the vulnerability. 2. Restrict network access to the web management interfaces of Sharp MFPs by implementing network segmentation and firewall rules, allowing only trusted administrative hosts to connect. 3. Disable or limit remote management features if not required. 4. Monitor network traffic for anomalous or unusually long MFPSESSIONID cookie values that could indicate exploitation attempts. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics targeting buffer overflow attempts against Sharp MFP web interfaces. 6. Conduct regular security audits of multifunction printers and ensure they are included in vulnerability management programs. 7. Educate IT staff about the risks associated with network-connected printers and the importance of timely patching. 8. Consider isolating multifunction printers on dedicated VLANs to reduce the risk of lateral movement in case of compromise.