CVE-2024-55956 Cleo Multiple Products: dangerous file upload
In plain words: The program accepts files it should refuse, such as programs disguised as ordinary uploads. The attacker can place and run their own tools on the server.
Confirmed exploited by CISA on · US federal patch deadline Jan 7, 2025
What to do
- Install Cleo's security update for Multiple Products. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Cleo Multiple Products Unauthenticated File Upload Vulnerability
- Product
- Cleo Multiple Products
- CISA description
- 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.
- Type of flaw
- Dangerous file upload (CWE-276)
- Confirmed exploited
- Dec 17, 2024 — known to be used in ransomware attacks
- US federal patch deadline
- Jan 7, 2025
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Answering about CVE-2024-55956 ·
Questions about CVE-2024-55956
Is CVE-2024-55956 being exploited?
Yes. CISA added CVE-2024-55956 to its Known Exploited Vulnerabilities catalog on Dec 17, 2024, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2024-55956?
Install Cleo's security update for Multiple Products. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2024-55956?
Only if you use Cleo Multiple Products. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.