CVE-2024-55956
Cleo Harmony / VLTrader / LexiCom · Managed file transfer (MFT)
Cleo Multiple Products Unauthenticated File Upload Vulnerability
At a glance
Exploited. Added to CISA’s catalog of exploited vulnerabilities on December 17, 2024.
Used in ransomware attacks, according to CISA.
Affected product: Cleo Harmony / VLTrader / LexiCom (category Managed file transfer (MFT), indicative classification). Name in CISA’s catalog: Cleo Multiple Products.
What should I do?
Apply the patches or mitigations from Cleo; if none are available, stop using the product.
Deadline set by CISA for US federal agencies: 21 days (due January 7, 2025). It only binds those agencies, but it is a useful measure of urgency.
- The vendor’s specific advisory is listed in the NVD references: CVE-2024-55956 on the NVD website.
Original text of the required action (CISA)
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Timeline
- Vulnerability published Publication date (NVD)
- Exploitation confirmed Added to CISA’s KEV catalog
- CISA deadline Remediation deadline set for US federal agencies
The facts, with their sources
- Exploitation confirmed
- Yes, on December 17, 2024 Date added to the catalog of exploited vulnerabilities. Exploitation itself may have started earlier. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Ransomware
- Known use Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Hunt for compromise
- Not requested by CISA Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA required action
- Apply the patches or mitigations from Cleo; if none are available, stop using the product. Rewritten by this site from CISA’s original text. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CISA deadline
- January 7, 2025, 21 days Set for US federal agencies: a measure of urgency, not an obligation elsewhere. Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- Vulnerability published
- December 13, 2024 Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
- Product according to CISA
- Cleo Multiple Products Filed by this site under “Managed file transfer (MFT)” (indicative classification). Source: KEV catalog, collected September 29, 2026 at 14:57 UTC
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Technical detail of the score: attack vector, complexity, impact. Source: National Vulnerability Database (NVD), collected September 29, 2026 at 15:00 UTC
Severity and activity
FIRST’s EPSS model. Since exploitation is already confirmed, this figure is mostly useful to compare activity. Collected Sep 29, 2026.
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.
Official description from the NVD, collected Sep 29, 2026. CVE® description © The MITRE Corporation.
Cleo Harmony, VLTrader, and LexiCom, which are managed file transfer products, contain an unrestricted file upload vulnerability that could allow an unauthenticated user to import and execute arbitrary bash or PowerShell commands on the host system by leveraging the default settings of the Autorun directory.
Summary from CISA (KEV catalog).
CERT-FR advisories
No advisory among the latest CERT-FR publications this site follows. That does not mean there are none.
Information reused under the Open Licence 2.0 (Etalab); the date of last update is shown for each advisory. This site is neither affiliated with nor endorsed by ANSSI.
Sources for this page
- CISA KEV catalog: exploitation, date added, required action, deadline, ransomware.
- NVD (NIST): CVSS severity, publication date, description, vendor references.
- EPSS (FIRST): probability of exploitation.
- CERT-FR: advisories and alerts (in French).
- Brand and category: indicative classification by this site (method).