# CVE-2026-39453: Red Lion Controls N-Tron 700 Series denial of service via web URL

Source: https://junglewise.ai/threats/cve-2026-39453-navigating-to-a-certain-url-on-the-switch-s-web-server-causes-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-09. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-39453 · Severity: high · CVSS 8.3 · Published 2026-10-09

The Red Lion Controls N-Tron 700 Series is an industrial network switch used in critical infrastructure. A vulnerability allows an attacker to trigger repeated reboots by accessing a specific URL on the device's web interface, causing continuous service outages. An attacker with network access can automate this attack using standard tools to maintain a denial-of-service condition.

Technologies: [Red Lion Controls N-Tron 700 Series](https://junglewise.ai/threats/technologies/n-tron-700-series). Vendors: [Red Lion Controls](https://junglewise.ai/threats/vendors/red-lion-controls).

## Quick answers

**Is CVE-2026-39453 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39453 being exploited in the wild.

**How severe is CVE-2026-39453?** High severity, with a CVSS score of 8.3, published 9 October 2026.

**Which products and versions are affected?** Red Lion Controls N-Tron 700 Series <=Firmware 3.11.0, <=Bootloader 2.0.6.1.

**Is there a fix for CVE-2026-39453?** Yes: fixed in Firmware 3.11.1 or greater. Until then: Disable access to the web GUI on the device. Configure or disable SNMP communities to prevent unauthenticated access.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-09"},{"kind":"advisory","at":"2026-10-15"}] Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-39453 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-39453?** Check whether you run Red Lion Controls N-Tron 700 Series at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Firmware 3.11.1 or greater

Disable access to the web GUI on the device. Configure or disable SNMP communities to prevent unauthenticated access.</anigation>
<parameter name="timeline">[{"kind":"disclosed","at":"2026-10-09"},{"kind":"advisory","at":"2026-10-15"}]

## Technical details

A missing input validation or reachable assertion in the N-Tron 700 Series web server allows unauthenticated network access to a URL that triggers an uncontrolled reboot. The vulnerability requires network access to the device's web interface but no authentication. Exploitation causes immediate device reboot, which can be automated to maintain persistent denial-of-service; a fix is available in firmware version 3.11.1 or greater.

## Affected products

- Red Lion Controls N-Tron 700 Series <=Firmware 3.11.0, <=Bootloader 2.0.6.1

## References

- [https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-281-01.json](https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-281-01.json)
- [https://www.cisa.gov/news-events/ics-advisories/icsa-26-281-01](https://www.cisa.gov/news-events/ics-advisories/icsa-26-281-01)

## Related threats

- [Red Lion Controls N-Tron 700 Series plaintext credential storage in configuration](https://junglewise.ai/threats/cve-2026-39460-usernames-and-passwords-including-the-default-factory-credentials)
- [Red Lion Controls N-Tron 700 Series SNMP unauthenticated administrative access](https://junglewise.ai/threats/cve-2026-33367-snmp-can-be-used-to-perform-administrative-actions-such-as)
- [Red Lion Controls N-Tron 700 Series physical reset to factory settings](https://junglewise.ai/threats/cve-2026-33272-a-malicious-user-with-physical-access-to-the-device-can-boot-the)
- [Default factory credentials with administrative access are enabled and persist even after configuring other administrator accounts.](https://junglewise.ai/threats/cve-2026-32645-red-lion-controls-n-tron-700-series)
- [Red Lion Controls N-Tron 700 Series firmware authentication bypass](https://junglewise.ai/threats/cve-2026-29797-no-authentication-is-required-when-updating-firmware-or)