Unauthenticated code execution via unrestricted file upload
Published Oct 27, 2024 · Updated Jul 31, 2026
Unrestricted file upload in Cleo Harmony, VLTrader, and LexiCom before 5.8.0.21 allows remote attackers to execute code. The file-transfer framework writes attacker-controlled files into the autorun directory, where the applications immediately interpret and execute them. No authentication or user interaction is required, and successful exploitation grants code execution under the service account.
Summary
What happened
Unrestricted file upload in Cleo Harmony, VLTrader, and LexiCom before 5.8.0.21 allows remote attackers to execute code. The file-transfer framework writes attacker-controlled files into the autorun directory, where the applications immediately interpret and execute them. No authentication or user interaction is required, and successful exploitation grants code execution under the service account.
The record
- CVE
- CVE-2024-50623
- Published
- Oct 27, 2024
- Updated
- Jul 31, 2026
- Vendor
- Cleo
- Product
- Cleo VLTrader
- Classifications
- CWE-434, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 27, 2024CVE publishedPublication date reported by the CVE source.
- Dec 3, 2024Exploitation reportedMass exploitation of Cleo file-transfer servers
- Dec 13, 2024Exploitation reportedCISA Known Exploited Vulnerabilities catalog entry
- Jul 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <5.8.0.21
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Huntress Cleo arbitrary-file-write proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- CISA Known Exploited Vulnerabilities catalog entryknown exploited catalog
- Clop-linked zero-day attacks against Cleo productsransomware
- Mass exploitation of Cleo file-transfer serversreported exploitation
Technologies
Your stack
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Your stack
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