CVE-2025-66635 in Web Config
Summary
by MITRE • 12/16/2025
Stack-based buffer overflow vulnerability exists in SEIKO EPSON Web Config. Specially crafted data input by a logged-in user may execute arbitrary code. As for the details of the affected products and versions, see the information provided by the vendor under [References].
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Analysis
by VulDB Data Team • 12/16/2025
This vulnerability represents a critical stack-based buffer overflow in SEIKO EPSON Web Config software that poses significant security risks to networked printing environments. The flaw manifests when a logged-in user submits specially crafted data inputs through the web interface, creating an opportunity for remote code execution. This type of vulnerability falls under CWE-121 which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations on the program stack. The attack vector requires authentication since only logged-in users can exploit this weakness, but the privilege escalation potential remains severe as the execution occurs within the context of the web application's privileges.
The technical implementation of this vulnerability stems from improper input validation within the web configuration interface of EPSON's printer management software. When legitimate administrative users interact with the web-based configuration pages, the application fails to properly validate the length and content of user-supplied data before processing it in stack-allocated memory buffers. This deficiency allows an attacker who has already established authentication credentials to craft malicious input sequences that exceed the allocated buffer space, causing memory corruption that can be leveraged to overwrite return addresses and execute arbitrary code. The exploitation process typically involves carefully constructed input that triggers the buffer overflow, potentially allowing the attacker to gain full control over the affected system.
The operational impact of this vulnerability extends beyond simple code execution as it fundamentally compromises the integrity and confidentiality of networked printing environments. Organizations relying on EPSON printers with web configuration capabilities face potential compromise of their entire print infrastructure, as successful exploitation could lead to persistent backdoor access, data exfiltration, or further lateral movement within the network. The vulnerability affects systems where the EPSON Web Config service is actively running and accessible, making it particularly dangerous in enterprise environments where printers are often connected directly to internal networks without proper segmentation. This risk is amplified by the fact that many organizations maintain administrative access to printer web interfaces for routine maintenance, inadvertently creating attack surfaces that can be exploited by malicious actors with minimal initial access.
Mitigation strategies should focus on immediate vendor patch deployment and network segmentation to limit exposure of affected systems. Organizations must prioritize applying the latest firmware and software updates provided by SEIKO EPSON to address this vulnerability. Network administrators should implement strict access controls to limit who can reach the web configuration interfaces of printer devices, potentially through firewall rules or network access control lists that restrict access to trusted administrative workstations only. Additionally, monitoring for unusual activity patterns in printer web interfaces and implementing intrusion detection systems can help identify potential exploitation attempts. From a defense-in-depth perspective, organizations should consider disabling web configuration interfaces when not actively required for administration, as this reduces the attack surface significantly. The vulnerability's classification under ATT&CK technique T1210 - Exploitation of Remote Services and T1059 - Command and Scripting Interpreter indicates that exploitation could lead to persistent access and further system compromise, making proactive mitigation essential for maintaining overall network security posture.