Host and event action script regex validation can be bypassed in certain situations, leading to potential command injection

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-23920
StatePUBLISHED
AssignerZabbix
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-24 19:16:49 UTC
Updated2026-09-10 21:15:39 UTC
DescriptionHost 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.

Risk And Classification

Primary CVSS: v4.0 7.7 HIGH from [email protected]

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-78 | CWE-78 CWE-78 CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary7.7HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS7.7HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Primary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Zabbix Zabbix All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zabbix Zabbix affected 7.0.0 7.0.21 git Not specified
CNA Zabbix Zabbix affected 7.2.0 7.2.14 git Not specified
CNA Zabbix Zabbix affected 7.4.0 7.4.5 git Not specified

References

ReferenceSourceLinkTags
support.zabbix.com/browse/ZBX-27639 [email protected] support.zabbix.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Zabbix wants to thank YoKo Kho (@YoKoAcc) from PT ITSEC Asia, Tbk for submitting this report on the HackerOne bug bounty platform. (en)

Additional Advisory Data

Solutions

CNA: Update the affected components to their respective fixed versions.

Workarounds

CNA: It is possible to use \A and \z anchors in the regex validation as a workaround.

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