KEV Intelligence

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2024-55956

["Harmony"

Cleo / ["Harmony"

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Severity
CVSS 9.8 · Critical
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
93.8%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2024-55956 is an unauthenticated vulnerability affecting Cleo ["Harmony" and 2 other products. In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom before 5.8.0.24, an unauthenticated user can...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Cleo / ["Harmony".

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

["Harmony"

In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom before 5.8.0.24, an unauthenticated user can import and execute arbitrary Bash or PowerShell commands on the host system by leveraging the default settings of the Autorun directory.

Published
13 Dec 2024
Exploitation Reported
17 Dec 2024
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

ransomware nuclei_scanner metasploit nessus_scanner malware cisa

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 17 Dec 2024

Independent exploitation attestation added to the KEV Intelligence record.

Used in malware

CISA

Recorded 17 Dec 2024

Malware families have been linked to exploitation of this CVE.

Proof of concept available

Nuclei Templates

Recorded 28 Apr 2025

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
CISA First 2024-12-17 00:00 UTC
CVE 2026-08-05 04:30 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
0
User-Agents
0

Raw values available in Pro and Enterprise.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/multi/http/cleo_rce_cve_2024_55956.rb 28 Apr 2025
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2024/CVE-2024-55956.yaml 25 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

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

EPSS

93.8%

Weaknesses

Improper Neutralization of Special Elements used in a Command ('Command Injection') CWE-77

Recent mention · Google Threat Intelligence

Written by: Casey Charrier, James Sadowski, Clement Lecigne, Vlad Stolyarov Executive Summary Google Threat Intelligence Group (GTIG) tracked 75...

Written by: Casey Charrier, James Sadowski, Clement Lecigne, Vlad Stolyarov Executive Summary Google Threat Intelligence Group (GTIG) tracked 75 zero-day vulnerabilities exploited in the wild in 2024, a decrease from the number we identified in 2023 (98 vulnerabilities), but...

Read full advisory

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Cleo Harmony < 5.8.0.24 - File Upload Vulnerability

nuclei · Created Unknown

cleo_rce_cve_2024_55956

metasploit · Created Unknown

Metasploit module for CVE-2024-55956

Timeline

From disclosure to observed exploitation

  1. KEV confirmed by CVE

    Exploitation attested by an external source

  2. Metasploit module available

    Exploit module available

  3. Public PoC available

    Public proof-of-concept code published

  4. Nuclei template available

    Scanner coverage available

  5. Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  6. First public exploitation report

    Exploit observed in malware

  7. CVE published

    Vulnerability disclosed publicly

  8. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2024-55956

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2024-55956",
  "confidence": "Confirmed",
  "cvss_score": 9.8,
  "cvss_estimated": false,
  "epss_score": 0.93804,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

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