CVE-2021-27406: An attacker can take leverage on PerFact OpenVPN-Client versions 1.4.1.0 and prior to send the config command

Q: How do I fix CVE-2021-27406?

openvpn-client: upgrade to newer than 1.4.1.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-27406 being exploited?

CVE-2021-27406 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-27406 affect?

CVE-2021-27406 affects openvpn-client. Severity is high (CVSS 8.8). An attacker can take leverage on PerFact OpenVPN-Client versions 1.4.1.0 and prior to send the config command from any application running on the local host machine to force the back-end server into initializing a new open-VPN instance with

This month

HIGH 8.8UPGRADE

CVE-2021-27406 is a high-severity flaw (CVSS 8.8) affecting openvpn-client. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An attacker can take leverage on PerFact OpenVPN-Client versions 1.4.1.0 and prior to send the config command from any application running on the local host machine to force the back-end server into initializing a new open-VPN instance with arbitrary open-VPN configuration. This could result in the attacker achieving execution with privileges of a SYSTEM user.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-15, CWE-610
Published	2022-10-14
Last modified	2026-06-17

Publisher (CNA): ICS-CERT · Vendor: perfact

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

Am I affected?

Timeline

2022-10-14 17:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

perfact openvpn-client UPGRADE

Affected: <= 1.4.1.0

Fixed in: newer than 1.4.1.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openvpn-client || rpm -q openvpn-client || openvpn-client --version

2. UPGRADE to newer than 1.4.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openvpn-client

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openvpn-client

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-27406?

openvpn-client: upgrade to newer than 1.4.1.0. Exact commands for each OS are on this page.

Is CVE-2021-27406 being exploited?

CVE-2021-27406 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-2021-27406 affect?

CVE-2021-27406 affects openvpn-client. Severity is high (CVSS 8.8). An attacker can take leverage on PerFact OpenVPN-Client versions 1.4.1.0 and prior to send the config command from any application running on the local host machine to force the back-end server into initializing a new open-VPN instance with

How urgent is CVE-2021-27406?

Priority 48/100. High severity

Software pages

OpenVPN vulnerabilities

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References

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