CVE-2021-43716Public exploit

Arbitrary firmware installation via recomputable CRC32 check

Published Aug 18, 2026 · Updated Aug 18, 2026

Improper firmware verification in Epson EasyMP Network Updater 1.20 allows attackers to flash modified EH-TW5350 firmware via USB. The update routine treats reversible encryption and a CRC32 over attacker-derivable header data as authenticity checks, allowing a modified payload to pass after re-encryption and checksum recomputation. Exploitation requires physical USB access or delivery of a crafted image to an operator, and successful flashing permits persistent device control or a service interrupt.

CVSS severity9.8
Critical
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper firmware verification in Epson EasyMP Network Updater 1.20 allows attackers to flash modified EH-TW5350 firmware via USB. The update routine treats reversible encryption and a CRC32 over attacker-derivable header data as authenticity checks, allowing a modified payload to pass after re-encryption and checksum recomputation. Exploitation requires physical USB access or delivery of a crafted image to an operator, and successful flashing permits persistent device control or a service interrupt.

The record

CVE
CVE-2021-43716
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-347, T1542.001
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1542.001Pre-OS Boot: System Firmware

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo