CVE-2026-55601Public exploit

Command execution via unsafe execute-on-match quoting

Published Oct 13, 2026 · Updated Oct 13, 2026

Shell injection in MultiTail 7.1.5 and earlier allows attackers to execute commands via crafted execute-on-match input. The check_filter_exec() function in mt.c appends matched input inside double quotes, leaving command substitution active when execute_program() in exec.c passes the command to sh -c. Exploitation requires an enabled -ex or -eX rule and attacker influence over matching monitored input; commands run with the privileges of the user running MultiTail.

CVSS severity7.3
High
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Shell injection in MultiTail 7.1.5 and earlier allows attackers to execute commands via crafted execute-on-match input. The check_filter_exec() function in mt.c appends matched input inside double quotes, leaving command substitution active when execute_program() in exec.c passes the command to sh -c. Exploitation requires an enabled -ex or -eX rule and attacker influence over matching monitored input; commands run with the privileges of the user running MultiTail.

The record

CVE
CVE-2026-55601
Published
Oct 13, 2026
Updated
Oct 13, 2026
Vendor
Folkert van Heusden
Product
MultiTail
Classifications
CWE-78, T1059.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 7.1.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Folkert van Heusden · MultiTailversion=<= 7.1.5

Published CVSS scores

7.3Folkert van HeusdenCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059.004Unix Shell

Public exploit references

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Technologies

Your stack

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Your stack

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