Bug 2450868 (CVE-2026-23920)

Summary: CVE-2026-23920 zabbix: Zabbix: Arbitrary code execution via newline injection in script input validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Zabbix. Authenticated users can bypass input validation in host and event action scripts by injecting a newline character. This bypass occurs because the validation regex, which uses start-of-line (^) and end-of-line ($) anchors, operates in multiline mode. Successful exploitation allows an attacker to inject and execute arbitrary shell commands, potentially leading to full system compromise.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2450936, 2450946, 2450938, 2450943    
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Description OSIDB Bzimport 2026-03-24 19:02:41 UTC 
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.