Lantronix G520 Series Cellular Gateway
CISA details two high-severity flaws in Lantronix G520 gateways that can yield root code execution.
CISA advisory ICSA-26-272-01 covers Lantronix G520 Series Cellular Gateway firmware 2.6.0.4R6_stable, used in transportation, energy, and water systems. CVE-2026-84409 (CVSS 7.5) is cross-site scripting through update metadata that can lead to command execution in the administrative context. CVE-2026-91191 (CVSS 7.5) comes from disabled package signature checks and a production private key in the public SDK, allowing malicious packages to run as root. CISA says no known public exploitation has been reported.
- G520 firmware 2.6.0.4R6_stable is affected.
- CVE-2026-84409 is XSS via update metadata, CVSS 7.5.
- CVE-2026-91191 can let forged packages run as root.
- The public SDK contains a trusted production private key.
- CISA reports no known public exploitation.
Vulnerabilities mentionedAll →
- CVE-2026-844097.7—Stored XSS via HTTP updates in Lantronix G520 gatewaypublished · Lantronix G520 Series Cellular Gateway+1 related
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
CVE-2026-84409+1 related CVE | Stored XSS via HTTP updates in Lantronix G520 gateway Lantronix G520 Series cellular gateways retrieve software-update metadata over unencrypted HTTP and store part of that metadata for later use. A management interface returns the stored value in JSON, and the update web page inserts it directly as HTML, so attacker-controlled metadata can run as script (CWE-79). The same authenticated origin also exposes an interface that can run system commands as root, so script in the administrative context can lead to arbitrary code execution on the device. An attacker must be able to influence the HTTP update metadata and a user must interact with the update UI (CVSS 4.0 7.7, attack requirements present, user interaction required). The issue is not in CISA KEV and no public proof-of-concept is known. |
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Summary
Successful exploitation of these vulnerabilities could allow an attacker to replace software and execute arbitrary code with root privileges.
The following versions of Lantronix G520 Series Cellular Gateway are affected:
- G520 Series 2.6.0.4R6_stable (CVE-2026-84409, CVE-2026-91191)
| CVSS | Vendor | Equipment | Vulnerabilities |
|---|---|---|---|
| v3 7.5 | Lantronix | Lantronix G520 Series Cellular Gateway | Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), Improper Verification of Cryptographic Signature |
Background
- Critical Infrastructure Sectors: Transportation Systems, Energy, Water and Wastewater Systems
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: United States
Vulnerabilities
CVE-2026-84409
The device's update mechanism retrieves metadata for software updates over an unencrypted HTTP connection and stores portions of that metadata for later use. A management interface subsequently returns this stored value in a JSON response, and the web interface responsible for displaying update information inserts that value directly into the page as HTML. This behavior allows attacker‑controlled metadata to be interpreted as script content. In addition, the same authenticated origin provides an interface capable of executing system‑level commands with root privileges. An attacker able to influence update metadata could exploit these conditions to execute arbitrary code within the administrative context of the device.
Affected Products
Lantronix G520 Series Cellular Gateway
Vendor:
Lantronix
Product Version:
Lantronix G520 Series: 2.6.0.4R6_stable
Product Status:
known_affected
Relevant CWE: CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Metrics
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 7.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| 4.0 | 7.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N |
CVE-2026-91191
The device's update mechanism includes conditions that allow unauthorized software packages to be accepted as authentic. During the boot process, the stock done function disables signature verification in the OPKG configuration before restoring optional packages from a writable, unsigned feed. Separately, the publicly distributed SDK contains the production private key whose corresponding public key is trusted by both stable and beta firmware builds. Either issue undermines package authenticity, and together they allow an attacker to provide packages that appear valid to the system. Even if signature enforcement is restored, the exposed production key enables an attacker to generate signatures that the device will continue to trust. An attacker who can supply a malicious package may be able to execute arbitrary code with root privileges during installation.
Affected Products
Lantronix G520 Series Cellular Gateway
Vendor:
Lantronix
Product Version:
Lantronix G520 Series: 2.6.0.4R6_stable
Product Status:
known_affected
Relevant CWE: CWE-347 Improper Verification of Cryptographic Signature
Metrics
| CVSS Version | Base Score | Base Severity | Vector String |
|---|---|---|---|
| 3.1 | 7.5 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H |
| 4.0 | 7.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
Acknowledgments
- Ievgen Bondarenko reported these vulnerabilities to CISA.
Legal Notice and Terms of Use
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities.
- Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
- Locate control system networks and remote devices behind firewalls and isolating them from business networks.
- When remote access is required, use more secure methods, such as virtual private networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
CISA also recommends users take the following measures to protect themselves from social engineering attacks:
- Do not click web links or open attachments in unsolicited email messages.
- Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
- Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.
No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.
Revision History
- Initial Release Date: 2026-09-29
| Date | Revision | Summary |
|---|---|---|
| 2026-09-29 | 1 | Initial Publication |