GPL Odorizers GPL750

View CSAF
Summary
Successful exploitation of this vulnerability could allow a low privileged remote attacker to manipulate register values, which would result in too much or too little odorant being injected into a gas line.
The following versions of GPL Odorizers GPL750 are affected:

GPL750 (XL4) >=v1.0|
GPL750 (XL4 Prime) >=v4.0|
GPL750 (XL7) >=v13.0|
GPL750 (XL7 Prime) >=v18.4|





CVSS
Vendor
Equipment
Vulnerabilities




v3 8.6
GPL Odorizers
GPL Odorizers GPL750
Missing Authentication for Critical Function




Background

Critical Infrastructure Sectors: Critical Manufacturing
Countries/Areas Deployed: Worldwide
Company Headquarters Location: United States


Vulnerabilities

Expand All +

CVE-2026-4436

A low-privileged remote attacker can send Modbus packets to manipulate register values that are inputs to the odorant injection logic such that too much or too little odorant is injected into a gas line.
View CVE Details

Affected Products
GPL Odorizers GPL750

Vendor:GPL Odorizers
Product Version:GPL Odorizers GPL750 (XL4): >=v1.0|<v6.0, GPL Odorizers GPL750 (XL4 Prime): >=v4.0|<v6.0, GPL Odorizers GPL750 (XL7): >=v13.0|<v20.0, GPL Odorizers GPL750 (XL7 Prime): >=v18.4|<v20.0
Product Status:known_affected


Remediations
MitigationGPL Odorizers recommends users update to the latest software version of the GPL750 in connection with the latest firmware from Horner Automation for the XL4, XL4 Prime, XL7, and XL7 Prime devices.https://lincenergysystems-my.sharepoint.com/:f:/p/h_baer/IgDYaHIhXpyLQJvnKPd6b80TAUgV7Lp8qmVYBFUb0lmr7ak?e=JLeADm.https://lincenergysystems-my.sharepoint.com/:f:/p/h_baer/IgDYaHIhXpyLQJvnKPd6b80TAUgV7Lp8qmVYBFUb0lmr7ak?e=JLeADm
MitigationGPL Odorizers recommends users clear the old files from their microSD cards, keeping only the LOGS folder and the FIRMWARE.LIC file if they have a WebMI license. The compressed folder downloaded from the link above can then be extracted to the root directory of the microSD card. These files already include the corresponding firmware update. If users do not have IT permissions to access their microSD cards, GPL Odorizers can provide preconfigured SD cards that technicians can simply swap into their odorizers prior to installation.
MitigationFor assistance in updating GPL Odorizers to the latest version, users should reach out to GPL Odorizers directly via phone number (303) 697-6701 during the hours of 8:00 a.m. to 4:00 p.m. MST.
MitigationHorner Automation offers firmware version 15.76 for their XL Series and version 17.30 for their XL Prime Series controllers https://hornerautomation.com/controller-firmware/. An installation guide is available for both the XL series and the XL Prime series.https://hornerautomation.com/controller-firmware/

Relevant CWE: CWE-306 Missing Authentication for Critical Function

Metrics




CVSS Version
Base Score
Base Severity
Vector String




3.1
8.6
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N








Acknowledgments

An anonymous researcher reported this vulnerability 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 this vulnerability. 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 this vulnerability has been reported to CISA at this time.

Revision History

Initial Release Date: 2026-04-09




Date
Revision
Summary




2026-04-09
1
Initial Publication




Legal Notice and Terms of Use

https://www.cisa.gov/news-events/ics-advisories/icsa-26-099-02

2026-04-09 12:00 UTC
--- FMail-lnx 2.3.2.6-B20251227
* Origin: TCOB1 A Mail Only System (2:263/1)