CVE-2021-40491

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV...

6.5 MediumFix available

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: None
Availability: None

Exploit likelihood

0.99%Up 0.2 points since Sep 3, 2021

What each source reports

NVD Score used 6.5

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: CVE-2021-40491
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:P/I:N/A:N
Weakness: CWE-345
Updated: 2026-11-02

CVE List No score

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: CVE-2021-40491
Updated: 2026-11-02

EUVDEUVD-2021-27668 No score

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: EUVD-2021-27668
Updated: 2026-11-03

GitHub AdvisoriesGHSA-qw8r-vcwc-vjc9 6.5

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV...

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: GHSA-qw8r-vcwc-vjc9
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Weakness: CWE-345
Updated: 2026-11-02

OSV 6.5

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: CVE-2021-40491
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Updated: 2026-11-07

OSVDEBIAN-CVE-2021-40491 6.5

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: DEBIAN-CVE-2021-40491
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-40491 6.5

The ftp client in GNU Inetutils before 2.2 does not validate addresses returned by PASV/LSPV responses to make sure they match the server address. This is similar to CVE-2020-8284 for curl.

Record: UBUNTU-CVE-2021-40491
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Updated: 2026-11-02

OSVUSN-5177-1 No score

inetutils vulnerability

It was discovered that Inetutils did not properly check the response of ftp requests. A remote attacker could use this vulnerability to cause a crash or run programs in the user machine.

Record: USN-5177-1
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`inetutils` Debian:12	before 2:2.2-1	2:2.2-1
`inetutils` Debian:13	before 2:2.2-1	2:2.2-1
`inetutils` Debian:14	before 2:2.2-1	2:2.2-1
`inetutils` Debian:10 From an advisory covering 2 CVEs	before 2:1.9.4-7+deb10u2, plus listed versions 2:1.9.4-72:1.9.4-7+deb10u1	2:1.9.4-7+deb10u2
`inetutils` Ubuntu:Pro:14.04:LTS	before 2:1.9.2-1ubuntu0.1~esm1, plus listed versions 2:1.9.1.306-0a482-12:1.9.1.363-bbc1-12:1.9.2-1	2:1.9.2-1ubuntu0.1~esm1
`inetutils` Ubuntu:Pro:16.04:LTS	before 2:1.9.4-1ubuntu0.1~esm2, plus listed versions 2:1.9.4-12:1.9.4-1build12:1.9.4-1ubuntu0.1~esm1	2:1.9.4-1ubuntu0.1~esm2
`inetutils` Ubuntu:Pro:18.04:LTS	before 2:1.9.4-3ubuntu0.1+esm1, plus listed versions 2:1.9.4-2build12:1.9.4-32:1.9.4-3ubuntu0.1	2:1.9.4-3ubuntu0.1+esm1
`inetutils` Ubuntu:Pro:20.04:LTS	before 2:1.9.4-11ubuntu0.1+esm1, plus listed versions 2:1.9.4-10build12:1.9.4-112:1.9.4-11ubuntu0.1	2:1.9.4-11ubuntu0.1+esm1

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 3, 2026	aliases	EUVD, OSV
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-40491 is a medium vulnerability (CVSS 6.5) in Gnu Inetutils, published September 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.99%, the 62nd percentile. Fixed in inetutils 2:2.2-1.

References

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