CVE-2026-73542 in Printers and Scanners
Summary
by MITRE • 08/20/2026
Multiple SEIKO EPSON printers and scanners contain revoked root certificates. A man-in-the-middle attack may allow an attacker to obtain communication data transmitted by the product. As for the details of the affected products and versions, refer to the vendor's information.
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Analysis
by VulDB Data Team • 08/20/2026
The discovery of revoked root certificates within multiple SEIKO EPSON printers and scanners represents a critical infrastructure security failure that undermines the fundamental trust model required for secure device communication. Root certificates serve as the anchor of trust in public key infrastructure systems, validating the authenticity of digital identities used during encrypted communications such as TLS or SSL sessions. When these foundational certificates are found to be revoked yet remain installed on embedded devices, it indicates a significant lapse in certificate lifecycle management and supply chain security verification processes by the vendor. This situation creates an environment where cryptographic validation mechanisms can be bypassed, allowing malicious actors to intercept sensitive data without detection by standard security protocols that rely on certificate validity checks.
From a technical perspective, this vulnerability exploits weaknesses in how embedded systems handle certificate revocation lists or online status checking mechanisms like Certificate Revocation Lists (CRL) and Online Certificate Status Protocol (OCSP). In many IoT and MFP environments, these validation processes are often disabled by default to reduce latency or due to limited processing capabilities. Consequently, even if a root certificate has been compromised and subsequently revoked by the issuing authority because its private key was exposed or it is no longer trusted, devices continue to accept connections signed with that certificate. This effectively nullifies the security benefits of encryption for any communication channel relying on these certificates, as attackers can present valid-looking but actually untrusted credentials during handshake negotiations.
The operational impact of this flaw is severe, particularly in enterprise environments where multifunction printers handle sensitive documents and network configurations. A successful man-in-the-middle attack enabled by this vulnerability allows an adversary to intercept, read, or modify communication data transmitted between the device and management consoles, cloud services, or other networked systems. This could lead to the exposure of confidential document contents scanned or printed through the device, theft of user credentials stored in configuration files, unauthorized modification of printer settings such as routing tables or security policies, and potential pivoting into deeper parts of the corporate network if the MFP is configured with excessive privileges. The persistence of these revoked certificates suggests that once deployed, devices may not receive timely updates to remove them, leaving a long-term attack surface open for exploitation.
This vulnerability aligns closely with CWE-295 Improper Certificate Validation and CWE-613 Insufficient Session Expiration, as it involves the failure to properly validate certificate status during connection establishment. In terms of adversary tactics, this scenario maps directly to MITMATT&CK Tactic TA0011 Command and Control under technique T1072 Software Deployment Tools or more specifically T1557 Adversary-in-the-Middle where attackers intercept communications between two parties who believe they are directly communicating. The use of compromised certificates is a classic indicator of compromise that security monitoring systems should flag, yet the presence of such certificates in firmware complicates detection efforts since traffic appears cryptographically valid to naive inspection tools.
Mitigation strategies must focus on immediate isolation and rigorous certificate management practices. Organizations should immediately identify all affected SEIKO EPSON devices within their network perimeter using asset discovery tools that scan for specific vendor fingerprints or known vulnerable versions. Network segmentation is critical; these devices should be placed in isolated VLANs with strict firewall rules limiting communication to only necessary services such as printing protocols and essential management interfaces, blocking direct internet access where possible. Administrators must verify whether the manufacturer has released firmware updates containing updated certificate stores that remove the revoked roots or implement proper revocation checking mechanisms. If no update is available, temporary mitigations include disabling unnecessary network services on the devices, enforcing strong authentication for all administrative access, and deploying deep packet inspection solutions capable of detecting anomalies in TLS handshakes involving known compromised certificates until permanent remediation can be applied through vendor patches or hardware replacement programs initiated by security teams monitoring CVE disclosures related to this issue.