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Epson Printers Scanners EUVDEUVD-2026-63198

| CVE-2026-73542 MEDIUM
Improper Following of a Certificate's Chain of Trust (CWE-296)
2026-08-20 jpcert GHSA-mw8v-5vg6-vwx7
6.3
CVSS 4.0 · Vendor: jpcert
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Gain network adjacency to target device
  2. Delivery
    Perform ARP/DNS spoofing to intercept traffic
  3. Exploit
    Present certificate under revoked root CA
  4. Execution
    Device accepts revoked certificate as trusted
  5. Impact
    Decrypt and read transmitted communication data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V12 - Secure Communication Certificate chain validation
Exploitation Conditions

Exploitation requires that the attacker achieve a man-in-the-middle network position between the affected Epson device and its remote communication endpoint - for example, through ARP poisoning, DNS spoofing, or rogue access point on a shared network segment (consistent with AC:H in the CVSS vector). The device must be actively transmitting data over a TLS connection that is validated against the revoked root certificate. No authentication or user interaction is required on the target device itself (PR:N, UI:N). Exploitation is limited to environments where the attacker can realistically intercept network traffic; devices on isolated, firewalled, or physically secured network segments are significantly harder to attack. The impact is limited to confidentiality - an attacker cannot modify data in transit or affect availability based on this vulnerability alone.

Impact

The CVSS 3.7 (Low) score reflects a realistic ceiling for this vulnerability: network-reachable (AV:N) but requiring high attack complexity (AC:H) - an attacker must successfully interpose themselves on the network path between the affected device and its remote endpoint. There is no integrity or availability impact (I:N, A:N), and confidentiality impact is limited (C:L). No EPSS data was provided in the input, and the vulnerability is not listed in the CISA KEV catalog, nor is any public proof-of-concept known at time of analysis. SSVC signals suggest low exploitation urgency: the attack is not automatable at scale given AC:H, and technical impact is partial confidentiality only. The practical concern is for environments where printers and scanners transmit sensitive documents over networks that are not otherwise protected - for example, organizations relying solely on device-level TLS rather than network segmentation. The absence of KEV listing and the high complexity bar meaningfully reduce priority compared to raw network-reachability might suggest.

Exploit ScenarioDerived

An attacker with access to the network path between an affected Epson printer or scanner and a remote service - for example, via ARP spoofing on a local network segment - presents a certificate issued under one of the revoked root certificates still trusted by the device. The device accepts the certificate as valid, and the attacker establishes a TLS session that allows them to read the plaintext of transmitted data, which may include scanned document content, authentication tokens, or device telemetry. No public proof-of-concept exploit code has been identified for this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 20, 2026

Revoked root certificates embedded in multiple Seiko Epson printers and scanners expose device communications to interception via man-in-the-middle attacks. Affected products continue to trust certificates that have been revoked, violating the chain-of-trust model defined by CWE-296, and allowing a suitably positioned attacker to decrypt or read transmitted data. No active exploitation has been confirmed (no CISA KEV listing), and the high attack complexity required for network positioning limits real-world exposure, but confidentiality of printer/scanner communications - potentially including scanned document content - is at risk.

RemediationAI

The primary remediation path is to apply firmware updates provided by Seiko Epson that replace or distrust the revoked root certificates; consult the vendor advisory at https://www.epson.jp/news/info/a-security202608.htm for model-specific firmware versions and update instructions. No exact fixed firmware version number is available in the current CVE record - affected version details are deferred to the vendor. As a compensating control where firmware updates cannot be applied immediately, network segmentation should be used to isolate printers and scanners from untrusted network segments, reducing the feasibility of MitM positioning (this limits but does not eliminate risk for devices communicating over shared infrastructure). Additionally, routing printer/scanner traffic through a network proxy that enforces current certificate revocation status (via OCSP or CRL) can detect and block connections relying on the revoked roots. Note that proxy interception introduces its own certificate trust requirements and should be implemented with care.

Affected VersionsENISA

Multiple SEIKO EPSON printers and scanners see the information provided by the vendor

Affects your stack

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Technical ContextAI · show details

CWE-296 (Improper Following of Chain of Trust for Certificate Validation) describes a failure where software continues to accept or use certificates that have been revoked, undermining the PKI trust model. In this case, affected Seiko Epson printers and scanners embed root certificates that have since been revoked by the issuing authority. When these devices establish TLS/SSL connections - for example, to cloud print services, firmware update endpoints, or network scan destinations - they may still validate certificates issued under the revoked roots as trustworthy. The CPE string 'cpe:2.3:a:seiko_epson_corporation:multiple_seiko_epson_printers_and_scanners:*:*:*:*:*:*:*:*' indicates a broad swath of the Epson product line is affected, though exact models and firmware versions are deferred to the vendor advisory. The network attack vector (AV:N) and high complexity (AC:H) in the CVSS vector are consistent with an MitM scenario requiring active network positioning.

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Severity by source

Vendor (jpcert) PRIMARY 6.3 LOW
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 3.7 LOW

MitM requires high-complexity network positioning (AC:H); no privileges or interaction needed; impact is limited to partial confidentiality of transmitted data.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (jpcert).

CVSS VectorVendor: jpcert

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

3
Severity Changed
Aug 20, 2026 - 06:22 NVD
LOW MEDIUM
CVSS changed
Aug 20, 2026 - 06:22 NVD
3.7 (LOW) 6.3 (MEDIUM)
CVE Published
Aug 20, 2026 - 05:16 cve.org
LOW 3.7

DescriptionCVE.org

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.

Threat Intelligence Overview

EPSS Score
0.1%
Top 99% exploitable
Prevalence
High
Epson is a global leader in consumer and enterprise printers and scanners
Social Media
1
Sightings
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
High
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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