---
id: CVE-2026-23920
title: >-
  Host and event action script input is validated with a regex (set by the
  administrator), but the validation runs in multiline mode
summary: >-
  Host and event action script input is validated with a regex (set by the
  administrator), but the validation runs in multiline mode. If ^ and $ anchors
  are used in user input validation, an injected newline lets authenticated
  users bypass…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
vendor: zabbix
product: zabbix
affected:
  - 'zabbix >= 7.0.0, < 7.0.22'
  - 'zabbix >= 7.2.0, < 7.2.15'
  - 'zabbix >= 7.4.0, < 7.4.6'
patched:
  - zabbix 7.4.6
published: '2026-03-24'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T21:15:39.950'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-23920'
references:
  - url: 'https://support.zabbix.com/browse/ZBX-27639'
    label: security@zabbix.com
tags:
  - nvd
epss: 0.00297
epssPercentile: 0.22582
ingestedAt: '2026-09-10T22:07:00.624Z'
---

## Overview

Host and event action script input is validated with a regex (set by the administrator), but the validation runs in multiline mode. If ^ and $ anchors are used in user input validation, an injected newline lets authenticated users bypass the check and inject shell commands.

## Affected

- `zabbix >= 7.0.0, < 7.0.22`
- `zabbix >= 7.2.0, < 7.2.15`
- `zabbix >= 7.4.0, < 7.4.6`

## Remediation

Upgrade past the affected range:

- `zabbix 7.4.6`