CVE-2021-41636: MELAG FTP Server 2.2.0.4 allows an attacker to use the CWD command to break out of the FTP servers root direct

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MEDIUM 6.5DOWNGRADE

CVE-2021-41636 is a medium-severity flaw (CVSS 6.5) affecting ftp server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

MELAG FTP Server 2.2.0.4 allows an attacker to use the CWD command to break out of the FTP servers root directory and operate on the entire operating system, while the access restrictions of the user running the FTP server apply.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.5% (top 27%)
CISA exploited list	No
Weakness	CWE-22
Published	2022-06-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: melag

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-06-24 12:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

melag ftp server DOWNGRADE

Affected: 2.2.0.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.2.0.4

1. Check installed version

apt-cache policy ftp-server || rpm -q ftp-server || ftp-server --version

2. No fixed release: DOWNGRADE to a release before 2.2.0.4 (Debian / Ubuntu)

apt-cache madison ftp-server sudo apt install ftp-server=<VERSION_BEFORE_2.2.0.4> sudo apt-mark hold ftp-server

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ftp-server sudo dnf downgrade ftp-server-<VERSION_BEFORE_2.2.0.4> sudo dnf versionlock add ftp-server

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41636?

ftp server: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-41636 being exploited?

CVE-2021-41636 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41636 affect?

CVE-2021-41636 affects ftp server. Severity is medium (CVSS 6.5). MELAG FTP Server 2.2.0.4 allows an attacker to use the CWD command to break out of the FTP servers root directory and operate on the entire operating system, while the access restrictions of the user running the FTP server apply.

How urgent is CVE-2021-41636?

Priority 46/100. Public exploit reference

Related CVEs

CVE-2026-6265 HIGH 8.8 UPGRADE Insecure preserved inherited permissions vulnerability in Cerberus FTP Server on Windows allows Privilege Esca
CVE-2025-5331 HIGH 7.3 DOWNGRADE A vulnerability has been found in PCMan FTP Server 2.0.7 and classified as critical
CVE-2025-5635 HIGH 7.3 DOWNGRADE A vulnerability classified as critical was found in PCMan FTP Server 2.0.7
CVE-2024-0731 MEDIUM 5.3 DOWNGRADE A vulnerability has been found in PCMan FTP Server 2.0.7 and classified as problematic
CVE-2024-0732 MEDIUM 5.3 DOWNGRADE A vulnerability was found in PCMan FTP Server 2.0.7 and classified as problematic

References

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