CVE-2021-43716 in EasyMP
Summary
by MITRE • 08/18/2026
Verification Bypass vulnerability exists in EPSON 150075647YWWV110 EasyMP Network Updater Ver.1.20. The Epson projector can be updated by encrypted firmware through USB.
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Analysis
by VulDB Data Team • 08/18/2026
The identified vulnerability represents a critical verification bypass within the EPSON EasyMP Network Updater utility, specifically version 1.20 associated with hardware identifier 150075647YWWV110. This flaw fundamentally undermines the integrity of the firmware update process for Epson projectors that support updates via encrypted firmware files transferred through a USB interface. In secure systems, any mechanism designed to apply critical system changes such as firmware upgrades must rigorously validate the authenticity and integrity of the incoming data before execution. The absence or failure of this validation step allows an attacker who has physical access to the device's USB port to inject maliciously crafted firmware images that bypass security checks intended to ensure only authorized, vendor-signed updates are applied.
From a technical perspective, the core issue lies in the insufficient verification logic within the updater software running on the projector or potentially within the companion utility if it interacts directly with the update mechanism. When an encrypted firmware file is presented via USB, the system fails to adequately verify cryptographic signatures or checksums against known trusted sources before proceeding with the installation. This lack of strict authentication means that any entity capable of generating a validly formatted but malicious payload can trick the device into accepting and executing it. The encryption aspect mentioned in the description may provide confidentiality for data at rest, but without proper integrity verification upon ingestion, it does not prevent an attacker from replacing legitimate encrypted modules with their own crafted equivalents if they possess or can reverse-engineer the necessary keys or exploit weaknesses in the decryption routine that precedes validation.
The operational impact of this vulnerability is severe, as firmware updates typically run at a privileged level within the device's embedded operating system. Successfully exploiting this flaw allows an attacker to achieve arbitrary code execution on the projector hardware. This could lead to complete compromise of the device, enabling persistent backdoors, denial-of-service conditions by flashing corrupted or incompatible firmware that bricks the unit, or using the compromised projector as a pivot point for further network attacks if it possesses network connectivity features inherent in modern smart projectors. The attacker does not need complex remote access; physical proximity and USB insertion are sufficient to trigger the vulnerability, making it particularly dangerous in public display environments such as conference rooms, lecture halls, or digital signage installations where devices may be left unattended with ports accessible.
This type of flaw is commonly categorized under CWE-287 Improper Authentication, specifically relating to authentication bypass during critical system operations. It also aligns with MITRE ATT&CK techniques involving Supply Chain Compromise and Peripheral Device Control, as the attack vector relies on manipulating external hardware interfaces to alter core system software. The vulnerability highlights a common pitfall in embedded device development where convenience of updating is prioritized over rigorous security validation protocols. Developers must ensure that all firmware updates are signed with strong cryptographic keys and that the receiving device verifies these signatures against a trusted root certificate before any installation process begins.
Mitigation strategies for this issue require both immediate administrative actions and long-term architectural fixes. Administrators should immediately restrict physical access to projector USB ports using port locks or by disabling unused interfaces if supported by the firmware settings. It is crucial to verify that no unauthorized devices are connected to these projectors in shared spaces. Furthermore, organizations must ensure they are running the latest available version of the EasyMP Network Updater and projector firmware released by Epson, as vendors typically address such verification bypasses through patches that enforce strict signature validation. Until updates are applied or physical access is controlled, reliance on this specific update method should be suspended in favor of more secure management protocols if available.