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CVE-2024-50623

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Cleo products. For every flaw being used in attacks, see Exploited flaws.

CVE-2024-50623 is a security flaw in Cleo products, software companies use to send and receive files. Attackers can run their own code on Cleo products. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 13 Dec 2024, and says ransomware gangs have used it.[1]

Cleo products is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Cleo has published a fix or advice.

Description

CISA calls it an unrestricted file upload in Cleo Multiple Products. In its words: “Cleo Harmony, VLTrader, and LexiCom, which are managed file transfer products, contain an unrestricted file upload and download vulnerability that can lead to remote code execution with elevated privileges.”[1]

The underlying weakness is unrestricted file upload (CWE-434), in MITRE’s list of common software weaknesses.[2]

It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]

Affected versions

NVD’s record doesn’t list version ranges for it; Cleo’s advisory has them[3]. CISA names the product as Cleo Multiple Products.

Most families won’t have Cleo products; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 13 Dec 2024, 46 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 3 Jan 2025 to fix it.[1] CISA says ransomware gangs have used it.

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 99%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

CISA doesn’t say who was attacked, or how.

Fix

Cleo has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.”[1]

  1. Check whether you use it.Cleo products is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 3 Jan 2025 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks, noting that ransomware gangs have used it.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 99%.[4]

See also

Other Cleo products flaws

Other unrestricted file upload flaws

  • CVE-2026-48356, Adobe Commerce and Magento: unrestricted upload of file with dangerous type ·
  • CVE-2026-56291, Balbooa Forms: unrestricted upload of file with dangerous type ·
  • CVE-2026-48939, iCagenda: unrestricted upload of file with dangerous type ·
  • CVE-2026-48908, JoomShaper SP Page Builder: unrestricted upload of file with dangerous type ·
  • CVE-2024-7694, TeamT5 ThreatSonar Anti-Ransomware: unrestricted upload of file with dangerous type ·

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Cleo Multiple Products Unrestricted File Upload Vulnerability”. Known Exploited Vulnerabilities Catalog, added 13 Dec 2024.
  2. ^ National Institute of Standards and Technology. “CVE-2024-50623 Detail”. National Vulnerability Database, published 28 Oct 2024.
  3. ^ Cleo. Advisories and fixes: support.cleo.com, support.cleo.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.986, percentile 99.9, 31 Oct 2026.
  5. CVE Program. “CVE-2024-50623”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.