---
id: CVE-2026-55601
title: MultiTail is a utility for monitoring multiple log files in one terminal
summary: >-
  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, the…
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
vendor: folkertvanheusden
product: multitail
affected:
  - multitail <= 7.1.5
published: '2026-10-13'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:04:29.760'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55601'
references:
  - url: >-
      https://github.com/folkertvanheusden/multitail/commit/84f304e140261034e33796bab81e9bf4f09d153c
    label: security-advisories@github.com
  - url: 'https://github.com/folkertvanheusden/multitail/issues/56'
    label: security-advisories@github.com
  - url: >-
      https://github.com/folkertvanheusden/multitail/security/advisories/GHSA-54vm-wwx8-856h
    label: security-advisories@github.com
  - url: >-
      https://github.com/folkertvanheusden/multitail/security/advisories/GHSA-54vm-wwx8-856h
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00214
epssPercentile: 0.11604
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-13T20:02:02.281948Z'
ingestedAt: '2026-10-13T20:53:44.638Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.