Bug 2551789 (CVE-2026-55601)

Summary: CVE-2026-55601 multitail: multitail: Arbitrary command execution via improper input escaping in execute-on-match feature
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 MultiTail. When using the execute-on-match feature, MultiTail fails to properly sanitize matched log data before passing it to the system shell for command execution. An attacker capable of influencing the contents of monitored input can exploit this issue by injecting shell metacharacters, resulting in arbitrary command execution with the privileges of the user running MultiTail.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2552159, 2552160    
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Description OSIDB Bzimport 2026-10-13 21:01:03 UTC 
MultiTail is a utility for monitoring multiple log files in one terminal. In version 7.1.5 and earlier, the -ex and -eX execute-on-match feature appended attacker-controlled matched input to a configured command inside double quotes, then check_filter_exec() in mt.c passed the constructed command through execute_program() in exec.c to sh -c. Partial escaping left shell metacharacters such as command substitution active, allowing an attacker who could influence monitored input to execute commands as the user running MultiTail. No fixed release is available as of this review.