How severe is CVE-2024-55956?

CVE-2024-55956 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2024-55956?

Affected package information for CVE-2024-55956 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2024-55956?

No fixed version has been published for CVE-2024-55956 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2024-55956 actively exploited in the wild?

Yes. There are 3 known exploit references for CVE-2024-55956, including 3 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2024-55956?

CVE-2024-55956 has an EPSS (Exploit Prediction Scoring System) score of 91.2%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2024-55956 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2024-55956 (Cleo Multiple Products Unauthenticated File Upload Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2024-12-17. CISA required all US federal civilian agencies to remediate this vulnerability by 2025-01-07. The required action was: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. This CVE has been used in known ransomware campaigns. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2024-55956?

CVE-2024-55956 is classified as CWE-77 (CWE-77). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2024-55956?

CVE-2024-55956 affects cleo harmony; cleo lexicom; cleo vltrader. Check the affected-products list on this page against your deployed version to confirm exposure.

Is there exploit tooling available for CVE-2024-55956?

A Nuclei detection template exists for CVE-2024-55956, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2024-55956 published, and has it been updated?

CVE-2024-55956 was published on December 13, 2024 and was last updated on November 4, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2024-12-17 — agencies required to remediate by 2025-01-07 · Ransomware

CVE-2024-55956

CRITICAL

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…

Published

Dec 13, 2024

Updated

Nov 4, 2025

Affected

0 pkgs

Patched

None yet

Exploits

3 known

EPSS Exploitation Probability

via FIRST.org ↗

91.2%probability of exploitation in next 30 days

Very High Risk100th percentile+2.08%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

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.

Affected Products

3 products · 3 configurations

Application

harmonycleo

< 5.8.0.24

range

Application

lexicomcleo

< 5.8.0.24

range

Application

vltradercleo

< 5.8.0.24

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom b…

cisa.govCISADec 2024

In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom b…

huntress.comNVDDec 2024

In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom b…

github.comMetasploitJan 2025

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2024-55956 in your stack?

O3 detects CVE-2024-55956 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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