CVE-2026-23920
Received Received - Intake

Command Injection via Regex Bypass in Zabbix Host Action Scripts

Vulnerability report for CVE-2026-23920, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-03-24

Last updated on: 2026-03-24

Assigner: Zabbix

Description

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.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-03-24
Last Modified
2026-03-24
Generated
2026-07-06
AI Q&A
2026-03-24
EPSS Evaluated
2026-07-05
NVD
EUVD

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-78 The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Attack-Flow Graph

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Executive Summary

This vulnerability occurs because the host and event action script input is validated using a regular expression that runs in multiline mode. When the validation uses the ^ and $ anchors, an injected newline character allows authenticated users to bypass the validation check and inject shell commands.

Impact Analysis

The vulnerability allows authenticated users to bypass input validation and inject shell commands. This can lead to unauthorized command execution on the affected system, potentially compromising system integrity, confidentiality, and availability.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

I don't know

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