CVE-2026-4436 PUBLISHED

GPL Odorizers GPL750 Missing Authentication for Critical Function

Assigner: icscert
Reserved: 19.03.2026 Published: 09.04.2026 Updated: 09.04.2026

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.

Metrics

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

Product Status

Vendor GPL Odorizers
Product GPL750 (XL4)
Versions Default: unaffected
  • affected from v1.0 to v6.0 (excl.)
Vendor GPL Odorizers
Product GPL750 (XL4 Prime)
Versions Default: unaffected
  • affected from v4.0 to v6.0 (excl.)
Vendor GPL Odorizers
Product GPL Odorizers GPL750 (XL7)
Versions Default: unaffected
  • affected from v13.0 to v20.0 (excl.)
Vendor GPL Odorizers
Product GPL Odorizers GPL750 (XL7 Prime)
Versions Default: unaffected
  • affected from v18.4 to v20.0 (excl.)

Solutions

Horner Automation offers firmware version 15.76 for their XL Series and version 17.30 for their XL Prime Series controllers. An installation guide is available for both the XL series and the XL Prime series. https://hornerautomation.com/controller-firmware/

Credits

  • An anonymous researcher reported this vulnerability to CISA. finder

References

Problem Types

  • CWE-306 CWE