External risk intelligence

Plaintext Credentials in Configuration File via SNMP TFTP Transfer.

CVE advisorySeverity: CRITICAL (CVSS 9.3)

CVE-2026-39460

The vulnerability involves SNMP and TFTP services, which are typically managed within internal or isolated operational technology networks. While these protocols can be exposed to the internet, they are generally not intended for public-facing access, and the requirement for specific configuration interactions makes widespread public internet reachability less common than standard web or edge services.

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This advisory details a vulnerability where sensitive credentials, including default ones, are stored in plaintext within configuration files. These files can be accessed through the command line or exported via TFTP, which can be initiated without authentication using SNMP. This could allow an attacker with administrator privileges to obtain these credentials.

Plaintext credentials stored in accessible files.
Information disclosure impacts sensitive access controls.
Confirm relevance and exposure for your environment.

Attack Path

How an attacker could exploit the issue

An attacker with low privileges could access sensitive credentials stored in plaintext within a configuration file. This file can be accessed via the command line interface or exported using TFTP, which can be initiated through an unauthenticated SNMP request. This exposure of sensitive information could then be leveraged for further malicious activities.

Requires low privileges to access.
Triggered by exporting configuration via TFTP.
Exposes sensitive credentials for misuse.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could expose sensitive information like usernames and passwords stored in device configuration files. When administrator rights are available, these credentials can be accessed via the CLI or exported through a TFTP transfer initiated from the web interface. A TFTP transfer can also be triggered using SNMP without requiring authentication, when supported by the advisory.

Usernames and passwords may be exposed.
Via unauthenticated TFTP or authenticated CLI/web export.
Unauthorized access to the system could occur.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability impacts systems where usernames and passwords, including default credentials, are stored in plaintext within configuration files, accessible via CLI or TFTP through SNMP without authentication. Identifying the scope and criticality of affected systems is the immediate priority, followed by confirming accountable owners and planning remediation.

Identify and confirm asset ownership.
Verify system reachability and criticality.
Plan remediation based on risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

Free EASM Trial See How Signal Works

Frequently asked questions

What is the product affected by CVE-2026-39460?

This CVE concerns devices manufactured by HMS Networks. These products are typically used in industrial and operational technology environments to manage communication and data exchange between different industrial protocols. They often serve as gateways or communication bridges, meaning they hold configuration data that controls how machines talk to each other, which is why protecting their internal settings is critical.

What is the weakness behind CVE-2026-39460?

This vulnerability is classified as CWE-522, which relates to insufficiently protected credentials. In plain terms, the device saves usernames and passwords in a readable, plaintext format within its configuration files rather than scrambling them with encryption. If an attacker gains access to these files, they do not need to perform complex decryption to steal valid login information for the device or potentially other connected systems.

How can an attacker trigger this vulnerability?

An attacker can obtain the configuration file through the device CLI if they have administrator rights, or by triggering a TFTP file transfer. Crucially, the TFTP transfer can be initiated via SNMP without needing any authentication. It is important to note that simply having the device running does not automatically expose the credentials; the process requires specific interaction with the SNMP or management interfaces to export the sensitive file.

Is my device at risk based on Halo Surface Signal?

Halo Surface Signal identifies this as a possible risk. While the vulnerability uses SNMP and TFTP—protocols often confined to internal or isolated operational technology networks—these can sometimes be exposed to the internet. Because these protocols are not intended for public-facing use, your risk depends heavily on whether these management services are reachable outside of your secure, private network boundaries.

How should I respond to CVE-2026-39460?

Begin by identifying which assets in your environment are running this technology and verifying their specific network reachability. Focus on whether SNMP or TFTP services are exposed to untrusted segments. Since this involves plaintext credentials, confirm who owns the affected devices, assess their criticality to your operations, and prepare a plan to manage these risks, such as restricting access to management interfaces.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.