CVE-2023-5347Public exploitNetwork attack vector

Unauthenticated OS replacement via forgeable firmware checksum

Published Jan 9, 2024 · Updated Oct 8, 2025

Improper firmware signature verification in Korenix JetNet Series firmware before 2024/01 allows remote attackers to replace the device OS. The cmd-server2 updater accepts a forgeable additive checksum over the image sections instead of verifying a cryptographic signature, allowing an altered root filesystem to pass validation. An unauthenticated TFTP upload followed by a crafted UDP packet to port 5010 initiates the flash write, enabling replacement of trusted executables or interruption of the device.

CVSS severity9.8
Critical
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper firmware signature verification in Korenix JetNet Series firmware before 2024/01 allows remote attackers to replace the device OS. The cmd-server2 updater accepts a forgeable additive checksum over the image sections instead of verifying a cryptographic signature, allowing an altered root filesystem to pass validation. An unauthenticated TFTP upload followed by a crafted UDP packet to port 5010 initiates the flash write, enabling replacement of trusted executables or interruption of the device.

The record

CVE
CVE-2023-5347
Published
Jan 9, 2024
Updated
Oct 8, 2025
Vendor
Korenix Technology
Product
JetNet Series
Classifications
CWE-327, CWE-347, CAPEC-552, CAPEC-642, CAPEC-558, T1542.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 8, 2025Record 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=firmware older than 2024/01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Korenix Technology · JetNet Seriesversion=firmware older than 2024/01

Published CVSS scores

9.8CyberDanubeCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
CWE-347Improper Verification of Cryptographic Signature
CAPEC-552Install Rootkit
CAPEC-642Replace Binaries
CAPEC-558Replace Trusted Executable
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

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Your stack

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