CVE-2021-41638Public exploitNetwork attack vector

File disclosure via premature user-account assignment

Published Jun 24, 2022 · Updated Aug 4, 2024

Improper authentication in MELAG FTP Server 2.2.0.4 allows remote attackers to read a user's files using only a valid username. The USER command assigns ClientConnection.RefUserAccount before any password check, and every FTP command treats that reference as authenticated. A valid, active FTP username and direct protocol control without a client-generated PASS command are required; LIST and RETR expose files in that account's base directory.

CVSS severity7.5
High
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in MELAG FTP Server 2.2.0.4 allows remote attackers to read a user's files using only a valid username. The USER command assigns ClientConnection.RefUserAccount before any password check, and every FTP command treats that reference as authenticated. A valid, active FTP username and direct protocol control without a client-generated PASS command are required; LIST and RETR expose files in that account's base directory.

The record

CVE
CVE-2021-41638
Published
Jun 24, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 24, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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