CVE-2023-5376VulnerabilityPublished 9 Jan 2024Updated 8 Oct 2025

CVE-2023-5376: Korenix JetNet Series · Missing Authentication

Affects Korenix JetNet SeriesSource CVE Database V5

Not known to be exploited · CVSS 8.6 High : upgrade to 2024 soon.

Data as of 26 Oct 2026, 07:57 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.4% chance of exploitation in 30 days – higher than 72% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2024

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Korenix JetNet Series to 2024.

Affected software

Product	Affected	Fixed in
Korenix JetNet Series	Affected <2024 =01	Fixed in 2024

AI-suggested

1. Immediately inventory all Korenix JetNet devices in your environment and identify firmware versions. 2. 3. Until patches are deployed, restrict network access to the TFTP service by implementing network segmentation and firewall rules that limit TFTP traffic to trusted management stations only. 4. Monitor network traffic for unusual TFTP activity, which may indicate exploitation attempts. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics targeting unauthorized TFTP usage. 6. Review device configurations and logs regularly to detect unauthorized changes. 7. Engage with Korenix support or vendor advisories for any interim mitigations or updates. 8. Incorporate this vulnerability into risk assessments and incident response plans focused on industrial control systems. 9. Educate operational technology (OT) and IT teams about the risks and signs of exploitation related to this vulnerability.

Description

An Improper Authentication vulnerability in Korenix JetNet TFTP allows abuse of this service. This issue affects JetNet devices older than firmware version 2024/01.

Impact

For European organizations, especially those operating in industrial automation, manufacturing, transportation, and critical infrastructure sectors, this vulnerability poses a significant risk. Exploitation can lead to unauthorized modification of device firmware or configurations, potentially causing operational disruptions, safety hazards, or enabling lateral movement within networks. Given the widespread use of Korenix JetNet devices in industrial Ethernet applications, compromised devices could affect production lines, traffic control systems, or energy distribution networks. The integrity breach could result in downtime, financial losses, regulatory non-compliance, and reputational damage. Since the vulnerability can be exploited remotely without authentication, attackers can target exposed devices over the internet or less-secure internal networks. The absence of known exploits currently provides a window for mitigation, but the high severity score indicates that the threat could escalate rapidly if exploited in the wild.

CWE-306Missing Authentication for Critical Function (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #21OWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Architecture and Design
Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment.
OWASP Cheat Sheets
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V1.2.3 (opens in a new tab)
V1.2.2 (opens in a new tab)
V1.2.4 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Force the System to Reset Values (opens in a new tab)
Using Unpublished Interfaces or Functionality (opens in a new tab)
Cross Site Request Forgery (opens in a new tab)
Communication Channel Manipulation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Oct 2025, 09:49 UTC

WeaknessesCWE-306

Technical details

References

Community reviews

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